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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Human physiology 26 (2000), S. 675-683 
    ISSN: 1608-3164
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The visual evoked potentials (EPs) in response to lateralized and central visual symbols under the conditions of involuntary (passive viewing) and selective attention (when one of the symbols was a target and required a rapid and precise motor reaction) are considered. The evoked potentials in the occipital, parietal, and frontal derivations were recorded in 20 healthy subjects. It was shown that the EP during selective attention are most pronounced and more alike in the parietal derivations. A strong positive correlation was revealed between the EP amplitude ([N1–P3] component) and the EP stability (correlation between the repeated EP). The involuntary and voluntary forms of attention supplement each other: the more expressed the involuntary attention (assessed by the [N1–P3] component) the higher the EP to target stimuli during voluntary attention and the shorter the reaction time. It is suggested that the role of visual attention consists in the increase and stabilization of cortical activity (primarily, the parietal regions) engaged in solving a visual task.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Neuroscience and behavioral physiology 27 (1997), S. 653-662 
    ISSN: 1573-899X
    Keywords: Systems activity of the brain ; cortical-subcortical interactions ; prefrontal cortex ; neostriatum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract This article presents the results of three series of experiments on cats, dogs, and lower primates, performed to investigate the structural, neurophysiological, and mediator mechanisms of the corticostriatal systems involved in the organization of behavior. Morphological studies of corticostriatal connections showed that along with the diffuse distribution of afferent terminals within the striatum, there were also elements of topical organization defined by anteroposterior and mediolateral gradients. Neurophysiological experiments on dogs and lower primates were used to study the spike activity of the prefrontal region of the cortex and the head of the caudate nucleus during training to conditioned first- and second-order reflexes and during the solution of complex problems involving delayed spatial selection. Studies demonstrated that while in dogs, most of the neurons recorded showed a transition to responses to the conditioned signal at a particular stage of carrying out a conditioned response, in monkeys all cells recorded showed specific responses at different periods of solving the task at all stages of the study. Neuropharmacological experiments on dogs showed that agents blocking glutamine receptors in the caudate nucleus had more pronounced effects at the phase of developing conditioned movement reflexes. Administration of these agents during the reflex reinforcement phase affected only the differentiation of inhibition. These results lead to the conclusion that the prefrontal area of the cortex and, to some extent, the caudate nuclei, act on incoming information specifying the current dominant need and the states of the external and internal environments, to carry out programmed actions and assess the results of these actions.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-899X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Influence of activation of cholinergic systems of the dorsal (Caudate-Putamen) and ventral (Accumbens) striatum on the process of the training of rats to active avoidance in a T-maze was investigated in experiments on 60 male Sprague-Dawley rats. The results, obtained on one and the same behavioral model (active avoidance in a T-maze), suggest the presence of particular features of the participation of the cholinergic systems of the dorsal and ventral striatum in the regulation of motor behavior. Thus, a one-time administration of carbacholine (Cbch, 0.03 μg) increases the level of correct responses on the first and succeeding days of the training of the rats to active avoidance, when microinjections are made into the right Accumbens, and also induces a significant increase in the level of correct realizations on the second and third days of training when microinjections are made in the left Accumbens, and at the same time, similar influences on the Caudate-Putamen do not induce any significant changes in the behavior of the animals during training in a T-maze. The changes in the locomotor activity according to collective data in the various groups of rats exhibited a generally complex character: from experiment to experiment, the level of the locomotor activity of the animals decreased in the majority of cases, but microinjections of the substances did not alter the locomotor activity of the animals in any of the groups. However, the degree of change in the level of locomotor activity in the group of rats with microinjections into the Accumbens (in this investigation, the degree of increase) very markedly depended on the localization of the cannula. The greatest effect was obtained in the lateral segment of this nucleus; this confirms the functional heterogeneity of this fairly small nuclear structure.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-899X
    Keywords: Biological feedback ; selective attention ; emotion ; motivation ; instrumental conditioning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The concept that functional psychopathology producing phobic syndromes is mediated by a specific deficiency in the integrative activity of the brain as a loss or partial limitation of the ability to recognize subjective experiences was used to develop a special method for mobilizing the selective attention of patients to the time course of subjective states. The fact of recognition of a state was demonstrated by the patient's ability to reproduce it by achieving specified parameters in a biological feedback test based on skin electrical responses. Success was positively reinforced by avoidance of an anxiously expected electrical stimulus. After successful training, patients could spontaneously adaptively correct their general daily behavior. Computer analysis of EEG traces revealed the specific structural-functional features of various states provoked during training.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-899X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In this paper the results of investigations of the participation of caudate nucleus neurons in the decision-making process and the process of organization of the program of a future motor response during the performance byMacaca mulatta monkeys of a delayed spatial choice tasks of varying degrees of complexity are presented. The presence in the caudate nucleus of spatially selective neurons, which are subdivided into two groups, was established: the position of conditional signals is reflected in the activity of one of the groups, and the direction of the future motor response is reflected in the activity of the other. The decision-making process is reflected in the impulse activity of neurons of the head of the caudate nucleus in two of its aspects: as the formation or choice of a specific motor program (spatially selective activity) and as a transitional factor from the instructive to the executive phase of the behavior.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-899X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract New data on the significance of mediator and peptidergic systems of the striatal level in the organization of alimentary conditioned reflexes are presented in this report. The role of acetylcholine-, dopamine-, GABA- and P- ergic systems of the caudate nucleus and the amygdala in the realization of positive and negative conditioned reflexes was investigated. The experiments were carried out on dogs with chemotrodes and microelectrodes implanted in subcortical structures. The results of the experiments with microinjections of the relevant substances into individual subcortical structures showed that activation of the same mediator system in various structures may lead to both unidirectional and multidirectional behavioral effects. On the other hand, the activation of various subcortical mediator systems can lead to identical changes in conditioned reflex activity. The effect of the administration of activators or blockers of a subcortical mediator system depends in many ways on the functional state of the nervous system at the moment of administration and on the localization of the microinjection. It is difficult to predict beforehand the role of various subcortical structures in the organization of integrated behavioral acts. The question of the necessity of studying mediator and peptidergic systems of each subcortical structure in order to understand their significance in the mechanisms of the conditioned reflex is raised.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Neuroscience and behavioral physiology 15 (1985), S. 502-510 
    ISSN: 1573-899X
    Keywords: orbital region of cortex ; classical second-order conditioned reflex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The reorganizations of the activity of neurons in the orbital cortex during the formation and realization of classical first- and second-order conditioned reflexes were studied in chronic experiments with eight dogs. An analysis of the histograms of the distribution of between-impulse intervals, poststimulus histograms, and the changes in the average discharge frequency showed that the responses of neurons to the presentation of a first-order or second-order conditioned signal (for a second-order reflex) undergo dynamic changes with the development and strengthening of conditioned connections. The pattern of impulse activity during the action of a conditioned signal approximates in form the pattern of discharges during the action of reinforcement. The data are discussed in light of E. A. Asratyan's concepts of the mechanism of formation of complex forms of conditioned reflexes.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Neuroscience and behavioral physiology 15 (1985), S. 494-501 
    ISSN: 1573-899X
    Keywords: amygdala ; conditioned signals ; activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The destruction of the amygdala in cats and dogs causes the animals to stop responding adequately to signals of various biological significance; the curves of change in the amplitude and probability of appearance of EPs in the sensorimotor cortex lose the maxima characteristic of intact animals at frequencies of 0.8, 1.6, and in the band from 2.0 to 3.0 kHz, which are the formant frequencies of certain communicational signals in cats. The assumption of a signal (food) significance by an indifferent stimulus, earlier without any biological meaning, finds reflection in the neuronal activity of the amygdala, which begins to respond to this signal as if to an unconditioned stimulus. On the basis of the above factors, the role of the amygdala is discussed in the evolution of the biological significance of conditioned stimuli and the differentiation of the afferent influences that reach it.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Neuroscience and behavioral physiology 27 (1997), S. 288-296 
    ISSN: 1573-899X
    Keywords: Cortical-subcortical interactions ; prefrontal cortex ; basal ganglia ; amygdaloid body ; neuron system activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Experimental data are discussed within the framework of the fundamental areas of studies of the neurophysiological mechanisms of behavior. The first of these is the study of the activity of individual neurons, which is characterized by plastic rearrangements based on synaptic, molecular (neurochemical), and submolecular (genetic) processes. The second area is the study of the activity of neuron systems, which unite the cells of different microgroups, and of systems including neural elements of different brain structures. Data on plastic rearrangements of neuronal activity in different structures during different types of behavior lead to the conclusion that the brain has special systems of relationships which characterize the interactions of blocks of neurons, in which the plasticity of a single neuron can maintain the integration processes of the whole system. Our own data, along with results of Russian and foreign physiological and clinical investigations, suggest that neurons unite into different functional blocks at different phases of conditioned reflex behavior, thus determining the dominance status of different centers and the vector of a purposive behavioral act in a given situation at a given time. Possible directions for further basic studies of the interactions between innate and phylogenetically acquired functionally specific neuron units are discussed on the basis of hypotheses which have been advanced to explain the neurophysiological organizational mechanisms of higher brain functions.
    Type of Medium: Electronic Resource
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