[The neurophysiological correlates of the organization and functioning of the cortical-caudate system in the formation and realization of conditioned-reflex behavior].
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Animals↗
Biomedical subjects
V T Shuvaev
Publications and source records attributed to V T Shuvaev.
[Comparative characteristics of neuronal activity of the frontal cortex and caudate nucleus of the monkey during realization of delayed behavior].
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Animals↗
[Scientific prognostication and the planning of fundamental research in the field of physiology].
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Academies and Institutes↗
[The participation of brain mediator and peptidergic systems in the mechanisms of the conditioned reflex].
In dogs with implanted chemotrodes and microelectrodes, the role of acetylcholine-, dopamine-, GABA- and P-ergic systems of the caudate nucleus and amygdala in positive and inhibitory conditioning, was studied. Activation of the same transmitter system in different structures could exert different behavioral effects, whereas activation of different transmitter subcortical systems could induce the same behavioral responses. The effects of activating or blocking agents upon the mediator subcortical system depended on the functional state of the nervous-system at the moment of administration as well as on the site of administration. It seems difficult to predict a contribution of one or another subcortical structure in organization of behavioral acts.
Amygdala↗
[Hippocampal control of the spike activity of neurons of the paraventricular nucleus of the hypothalamus in the lactating rat].
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Animals↗
[Role of the amygdala in the evaluation of the biological significance of conditioned stimuli].
Lesions of the amygdala in cats and dogs prevent some animals to respond adequately to signals of different biological significance; the amplitudes and probabilities of EPs appearance in the sensomotor cortex lose their maximums at 0.8 and 1.6 frequencies within the range of 2.0 to 3.0 kHz which are formant ones of some communication signals in cats. Rendering an indifferent stimulus a signal, i. e. food significance, becomes reflected in the amygdala neuronal activity, the amygdala starting to respond to the signal as if it were an unconditioned stimulus. The data obtained are used to discuss the role of amygdala in assessment of conditioned stimuli biological significance as well as in differentiation of incoming afferent influences.
Acoustic Stimulation↗
[Rearrangement of the activity of orbital cortex neurons during second-order classical conditioning].
In chronic experiments on 8 dogs, rearrangements of unit activity were studied in the orbital cortex in the course of classic conditioning of the I and the II order. Histograms of the interspike intervals distribution changes of the mean firing rate revealed that, in the course of conditioning, the neuronal responses to presentation of conditioned stimuli of the I and II order (for the II order reflexes) underwent dynamic changes. The unit activity pattern under the effect of a conditioned stimulus approximates the form of the pattern in reinforcement. The data are discussed in the light of E.A. Asratian's ideas of the mechanism for formation of complex forms of conditioned reflexes.
Action Potentials↗
[Review: orbito-caudate level of conditioned reflex organization].
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Animals↗
[Dynamics of orbital cortex neuronal activity upon stimulation of the amygdaloid complex].
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Amygdala↗
Involvement of the amygdala in evaluating the biological significance of conditioned stimuli.
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 format 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.
Amygdala↗
Reorganization of activity of neurons of orbital cortex during formation of classical second-order conditioned reflexes.
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. Asratvan's concepts of the mechanism of formation of complex forms of conditioned reflexes.
Animals↗
The participation of mediator and peptidergic systems of the brain in conditioned reflex mechanisms.
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.
Acetylcholine↗
Participation cholinergic systems of the dorsal and ventral striatum in the training of rats to avoidance in a T-maze.
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 microgram) 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.
Animals↗
Structure of neuronal activity of the caudate nucleus of monkeys during decision-making and the realization of the motor program in different variants of a delayed spatial choice task.
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 by Macaca 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.
Animals↗
Functional rearrangements in the human brain during emotional self-regulation with biological feedback.
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 specific 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.
Adult↗
Corticostriatal mechanisms of behavior.
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.
Action Potentials↗
Neurophysiological mechanisms of cortical-subcortical interactions in the organization of behavior.
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.
Animals↗
[Basal ganglia and behavior].
A comparative analysis of the most well known hypotheses of basal ganglia participation in organisation and control of behavioural functions, is presented.
Animals↗