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Biomedical subjects

K N Dudkin

Publications and source records attributed to K N Dudkin.

At least 19 recordsLinked to original sources
PubMed1998

[Dependence of learning characteristics on visual object properties in Rhesus macaca by bilateral removal of the 7th field of the parietal cortex].

Removal of the rhesus monkey parietal cortex 7th field exerted no effect on learning processes involving visual discrimination of images united in their colour and geometrical form, but the learning of differentiating the spatial information did suffer. The data obtained suggests that, in the process of learning visual differentiation, spatial differentiating signs are formed, the process involving neuronal structures of the 7th field of the inferior cortex. Removal of the 7th field disrupts mechanisms of the body scheme assession and egocentric orientation resulting from visual-vestibular interrelationships.

Animals↗
PubMed1998

[The model of adaptive primary image processing].

A computer model of adaptive segmentation of the 2D visual objects was developed. Primary image descriptions are realised via spatial frequency filters and feature detectors performing as self-organised mechanisms. Simulation of the control processes related to attention, lateral, frequency-selective and cross-orientation inhibition, determines the adaptive image processing.

Models, Neurological↗
PubMed1997

[The dependence of the characteristics of visual short-term memory in monkeys on the spatial properties of the images].

Specifics of spatial components induced a shorter information storage and more obvious motor responses as compared with other visual attributes of the stimulus (shape or colour) in rhesus monkeys. The findings suggest that the short-term memory mechanisms involve visual information processing in the visual system as well as spatial discriminative features maintained by the parietal cortical mechanisms involving visual-vestibular interactions.

Animals↗
PubMed1997

[The specific nature of the cholinergic mechanisms of short-term memory in monkeys for different types of visual information: the characteristics of the effect of amizil].

Short-term storage of visual information in monkeys seems to be determined by a set of cholinergic mechanisms, each of them dealing with a certain type of visual objects. These mechanisms are involved into the visual information processing and forming spatial discriminative features caused by the visual-vestibular interaction.

Animals↗
PubMed1995

[The neurophysiological correlates of improvement in the cognitive characteristics of monkeys with modification of the NMDA-ergic structures of the prefrontal cortex].

The effect of the NMDA glutamate agonist on cognitive characteristics and short-term memory (SM) was studied in rhesus monkeys. The NMDA effect manifested itself in doubling the SM term and in changing of the unit activity in the prefrontal cortex. The NMDA also induced a considerable increase in the cross-correlation coefficients between the unit responses in visual and prefrontal cortex. The data obtained suggest that the glutamatergic structures of prefrontal cortex take part in the processes of visual recognition and the SM in monkeys. The effect seems to improve the short-term memorizing of a visual information.

Animals↗
PubMed1995

[Synchronization processes in the mechanisms of short-term memory in monkeys: the participation of cholinergic and glutaminergic cortical structures].

Administration of amysil blocking M-cholinoreceptors, and APV the duration of short-term storing of information was decreased whereas the motor response time increased. This was followed by a considerable desynchronisation of the unit activity. The NMDA and APB improved the characteristics of the short-term memory. The role of synchronisation of the information processes in the short-term memory mechanisms and participation of cholinergic and glutamatergic systems in them, are discussed.

Acoustic Stimulation↗
PubMed1994

[The neurophysiological correlates of the processes of decision making in the cerebral cortex during visual recognition in monkeys].

In behavioral experiments on monkeys tested for a delayed visual differentiation of different colours stimuli, neuronal pools were recorded simultaneously in the visual, prefrontal and inferotemporal cortex. Wrong motor responses were always followed by considerable readjustments of the unit activity patterns whereas in right decisions a synchronisation and a cross-correlation occurred between neuronal pools. Possible mechanisms of the decision making and the reasons for the desynchronisation in wrong responses, are discussed.

Acoustic Stimulation↗
PubMed1994

[The dynamic impulse activity of the neocortical neurons in monkeys with the task of visual recognition after short-term oxygen starvation].

During a 2.5-min. hypoxia in monkeys, a rearrangement of the unit activity occurred in the visual and prefrontal cortex. Following this, the motor response in delayed visual spatial reaction tack did not restore during several hours. The rearrangement involved appearing of sequential phases of hyperactivation and inhibition. Duration of the posthypoxic inhibition and ratio of posthypoxic hyperactivation frequencies to the background one were significantly greater in the prefrontal cortex than in the visual one.

Acoustic Stimulation↗
PubMed1993

[The participation of the cholinergic structures of the prefrontal and inferotemporal cortices in visual recognition processes in monkeys].

Characteristics of visual recognition were impaired by amysil influence in monkeys. This was accompanied by a considerable activation of unit activity in the prefrontal cortex. Amysil induced a considerable drop in the cross-correlation coefficients between simultaneous responses of neuronal populations in prefrontal and inferotemporal cortex.

Acoustic Stimulation↗
PubMed1993

[The effect of an antioxidant on the neuronal impulse activity of the prefrontal and inferotemporal cortices during visual recognition in monkeys].

The antioxidant oxymetacil improved cognitive characteristics and activated neuronal activity in the monkey prefrontal area in the process of delayed visual differentiation of different colour stimuli. It also considerably increased the mutual correlation coefficients between neuronal responses in prefrontal and inferotemporal cortex. The data obtained suggest a contribution of neuronal structures of these areas into the improvement of the cognitive characteristics.

Acoustic Stimulation↗
PubMed1992

[Visual recognition processes in monkeys and their neuronal correlates in the visual cortex: the effect of an M-cholinoreceptor blocker].

Unit activity was studied in the visual cortex prior to and after amyzyl administration in monkeys trained for delayed visual differentiation of different colour stimuli. The data obtained suggests that the cholinergic mechanisms of the visual cortex are involved in the visual recognition and seem to play different functional roles at different stages of the behaviour.

Acoustic Stimulation↗
PubMed1992

[An improvement in the cognitive characteristics of monkeys induced by an antioxidant: the neurophysiological correlates in the visual cortex].

Administration of oximetacyl considerably improved the cognitive characteristics of the processes of delayed visual recognition, increased auto- and cross-correlation coefficients in the responses of groups of neurons. The data obtained suggests nootropic properties of oximetacyl and participation of visual cortex of the monkey brain in realisation of these properties for improvement of the cognitive characteristics.

Acoustic Stimulation↗