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Results for “CONDITIONED REFLEX”

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At least 271 records · Page 15Linked to original sources
PubMed2004

Functional asymmetry of the frontal cortex and lateral hypothalamus of cats during an operant food-related conditioned reflex.

The extent of correlation and the latency of evoked potentials to sound, recorded bilaterally in the frontal cortex and lateral hypothalamus of cats, were studied at different stages of the acquisition of an operant food-related reflex and during sudden transfer to 30% food reinforcement. High correlation coefficients between the evoked responses of the cortex and hypothalamus with left-sided dominance were seen in conditions of high levels of food motivation at the beginning of each experiment and in conditions of the high-probability appearance of the acquired conditioned reflex throughout the rest of the experiment. Comparison of the peak latencies of the early positive (P55-80) components of evoked potentials on the right and left sides showed that shorter latent periods were seen in the cortex on the left side at all behavioral stages, while this occurred (on the left side) in the hypothalamus only when the conditioned reflex was unfixed, while after fixation of the reflex and provision of 30% reinforcement, shorter latent periods were seen on the right side. It is concluded that the high level of left-sided correlation of evoked potentials in the hypothalamus was associated with the motivational and motor components of purposive behavior and was not associated with the emotional tension of the animals provoked by the disruption of the food reinforcement stereotype.

Acoustic Stimulation↗
PubMedDate not supplied

Conditioned reflex release of dopamine in the nucleus accumbens after disruption of the hippocampal formation in rats.

Vital intracerebral microdialysis combined with HPLC with electrochemical detection was used to study changes in dopamine release in the nucleus accumbens during the development and realization of an emotional conditioned response in hooded rats with lesions to the hippocampal formation. These studies showed that one month after bilateral administration of ibotenic acid into the hippocampal formation, rats had weakened emotional responses to contextual stimuli. The process of development of the conditioned reflex was accompanied by higher-level and longer-lasting release of dopamine in the nucleus accumbens than in sham-operated rats. Dopamine release levels in the nucleus accumbens during realization of the conditioned reflex to contextual stimuli in rats with hippocampal lesions and sham-operated rats were identical.

Animals↗
PubMedDate not supplied

[Effect of the new antidepressant, inkazan, on the bioelectrical activity of the brain and conditioned reflexes].

It has been shown in experiments on cats and rabbits that the new original antidepressant inkazan--3 methyl-8-methoxy-3H,1,2,5,6-tetrahydropyrazino (1,2,3-ab)-beta-carboline hydrochloride--exerts an activating action on EEG of the brain cortex, reticular formation of the midbrain and hippocamp. Inkazan administered in small doses facilitates the inhibition of the conditioned reflexes of avoidance in rats, while the increased doses inhibit these reflexes. Inkazan has both features in common with the tricyclic antidepressants but differs from them in its effect on bioelectrical activity of the brain and on conditioned reflexes.

Animals↗
PubMedDate not supplied

[Effect of early food deprivation on elaboration and preservation of a defensive conditioned reflex in rats].

A study was made of the influence of unlimited vs. insufficient feeding with mother's milk of fifteen litters of rats in early postnatal period on the rate of "incomplete" twofold learning (elaboration of a conditioned avoidance reflex) at the age of 30 and 90 days, and the degree of retention of conditioned reflexes in 30-second, 24-hour and two months intervals. The experiments were carried out in Fyodorov's modification of the apparatus with program control. A conditioned reflex of active avoidance of electric current was elaborated in response to a photic signal. It has been established that unlimited feeding of young rats with mother's milk has a positive influence in the early postnatal period on the general development, on the rate of twofold learning and the level of retention of a conditioned reflex, while unsufficient feeding has a negative influence on these characteristics.

Age Factors↗
PubMedDate not supplied

[The evolutionary aspects of the dynamic acquisition of simple conditioned reflexes].

The dynamics of elaboration of simple classical and instrumental conditioned reflexes in snails, rats, cars, dogs and humans was investigated. The dependence between the number of correct responses (in percentages) and the number of reinforcements was significantly approximated with exponential equation including the coefficient describing the initial level of conditioning. Regression analysis gave the opportunity to compare the dynamics of conditioning in different animal species.

Adult↗
PubMedDate not supplied

[Inhibitory effect of the amygdala on alimentary-conditioned reflexes in the dog].

In experiments on dogs, changes of conditioned alimentary reflexes were studied under stimulation (50-100 mcA, 1, 40, 100 imp/s, 0.5 ms) of the basolateral area of amygdala before and after electrolytic ablation (5 mA, 60 s) of the head of the caudate nucleus. Stimulation of the amygdala, which elicited inhibition of conditioned secretory reflexes and prolongation of latencies in intact dogs leads to opposite - activating - influences after destruction of the caudate nucleus head. A conclusion is made on the participation of neurophysiological and neurochemical mechanisms of the caudate nucleus in transmission of inhibitory effects of the amygdala on alimentary conditioned reflexes.

Amygdala↗
PubMed2003

[Principle of least action, physiology of vision, and conditioned reflexes theory].

The variation principles such as principle of least action by Maupertuis (1740) and Fermat principle (1660) are fundamental for physics. They permit to establish a property by which the actual state is differing from all possible states of the system. The variation approach permits to establish equation of motion and equilibrium of a material system on the basis of one common rule which reduces to the search of the function extremes, describes this property of the system. So for the optical systems, crucial is the time and not the length of the way. According to Fermat principles, the light "choosen" from all possible ways connects two dots in the way which needs the least time. Generality of the variation principles guarantees success of their use in brain function investigations. Between different attempts to apply the variation principles to psychology and linguistics, the Zipf principle of least effort must be distinguished. Zipf (1949) demonstrated that languages and some artificial codes satisfied the least principle. For the brain physiology, classical conditioned reflex theory is the ideal area of variation principles application. According to this approach, conditioning leads to finding the extreme during fixation of the temporal link. In vision, physiological investigations are difficult because the signal has many dimensions. For example, during perception of spatial properties of surrounding world, in vision is realized minimization (reduction) of spatial-frequency spectrum of the scene. The receptive fields provide optimal accumulation of the signal. In ontogenesis, signal--noise ratio becomes optimal as receptive fields minimized the internal noise spectrum. According to the theory of match filtration, in the visual system recognition is carryied out by minimal differences between the image description in the visual system and storage in the human memory template of that image. The variation principles help to discover the physical property of phenomenon. The law discovered for mechanical system may be translated to quantum level. In physiology, variation principles permit us to connect information approach with concrete physiological mechanisms of pattern recognition and conditioned reflex.

Conditioning, Classical↗
PubMedDate not supplied

[Effect of extirpation of the sensorimotor cortex on the formation of conditioned reflexes to a complex signal in the ontogeny of the cat].

In kittens of the age from 39 days to 4 months the influence was studied of the sensorimotor cortex (SMC) ablation on formation and preservation of previously elaborated reflex to a simultaneous complex stimulus (light + sound) with extinction of reaction to nonreinforced components of the complex signal. It is shown that SMC ablation in the age up to 2.5 months does not affect the formation or preservation of the conditioned reflex. The SMC ablation in preliminarily trained kittens in the age of 3.5 months and older leads to disinhibition of components differentiation with preservation of the positive conditioned reflex to the complex signal. In untrained kittens of the same age the SMC ablation leads to disability of animals to inhibit the motor reaction to differentiation signal. The question is discussed of SMC significance in the ontogenesis at formation of adequate forms of behaviour requiring heterosensory interaction.

Acoustic Stimulation↗
PubMedDate not supplied

[Alimentary instrumental conditioned reflexes in dogs with different types of nervous system].

Alimentary conditioned reflexes in the form of pressing (with an effort not less than 600 g) with a fore-leg on the pedal of a nearby feeding-trough, were elaborated by means of classical secretory technique in 15 dogs with defined typological characteristics of the higher nervous activity. The motor habit was formed in about a half of the animals. The ability to instrumental learning was assessed on a five-points scale in accordance with four stages of habit formation. The study revealed an absence of direct dependance between the obtained typological characteristics of the animals and their ability to instrumental conditioning.

Animals↗
PubMedDate not supplied

[The correlation between the changes in synaptic efficiency and cellular excitability in the acquisition of a conditioned reflex analog].

By calculating correlation coefficients was revealed the positive linear correlation between the conditioned changes of direct and indirect components of the pyramidal tract response pointing to a correlation between changes of synaptic efficiency and coincident shifts of cellular excitability. Coincidence of the maximal value of this connection with that of cellular excitability dependent on the activation of the lateral hypothalamus points to the role of this subcortical motivational structure in starting intracellular reactions leading to a formation of a common molecular substrate underlying interaction of the membrane and synaptic mechanisms. Precedence of the maximal manifestation of this interaction to the highest increase of synaptic efficiency testifies to the contribution of this process to the manifestation of the basic mechanism of conditioned reflex.

Animals↗
PubMed1987

[Role of monoamines in the recovery of the conditioned reflex activity of rats following extirpation of the frontal cortex].

The influence of frontal cortex extirpation on the amount of monoamines in the brain structures was investigated in chronic experiments on rats trained according to the method of motor feeding reflexes with bilateral reinforcement. Monoamine levels were measured by high performance liquid chromatography with electrochemical detection. By the ninth day after the ablation serotonin (5-HT) and dopamine (DA) levels were significantly reduced in the cortex and the striatum, respectively, while noradrenaline ++ (NA), 5-HT, dihydroxyphenylacetic and 5-hydroxyindoleacetic acid levels in raphe nuclei and locus coeruleus were increased. The level of conditioned reflex reproduction was 39% on the light and 33% on the sound stimulus. The involvement of monoamines in the recovery of conditioned reflexes after frontal cortex extirpation is discussed.

Animals↗
PubMed1977

Acquisition of appetitional and palpebral conditioned reflexes by the same infants.

The establishment of appetitional and palpebral conditioned reflexes was compared in three groups of 26 infants, 3--150 days old. The age range within each group at the beginning of conditioning was 0--20 days for both methods. The parameters compared were the time to reach equal criteria for the establishment of the conditioned response, and the nature of acquisition. The main results are as follows: (1) appetitional CR was established more quickly than palpebral CR; (2) the relative rates of conditioning in both methods were correlated in the same infants (r = 0.84; P<0.001); (3) the course of conditioning was in striking agreement in infants of the same age, both premature and full-term, for the two applied methods, but different for groups of infants of different ages. The results indicate that two quite different methods yield a picture of differences in the functional capacity of the CNS which are in close agreement with those for age.

Age Factors↗
PubMedDate not supplied

[Switching-over of homogeneous (alimentary) conditioned reflexes in rats following simultaneous lesions of the hippocampus and amygdala].

Conditioned switching-over of homogeneous (alimentary) conditioned reflexes was elaborated in intact rats and in rats with simultaneously lesioned hippocampus and amygdala; time of the day served as switching stimulus. The operated rats showed higher values of intersignal and conditioned motor activity and easier conditioned switching-over than intact animals. It is suggested that the lesion of the amygdala enhances the effect of accelerated elaboration of the switching-over observed in animals with lesioned hippocampus, due to the elimination of competing (non-alimentary) motivations.

Amygdala↗