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Results for “CONDITIONED REFLEX”

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PubMedDate not supplied

[Alimentary conditioned reflex behavior in the rat following injection of 6-hydroxydopamine into the caudate nucleus and nucleus accumbens].

In Wistar rats with degenerated dopaminergic terminals of the caudate and accumbens nuclei (administration of 6-hydroxydopamine, 30 mcg, bilaterally), an alimentary conditioned reflex was elaborated in a T-maze. Degeneration of the caudate nucleus terminals disturbed the elaboration, while degeneration of N. accumbens terminals did not affect the learning.

Animals↗
PubMedDate not supplied

Influence of quinolinic acid, an endogenous neurotoxin, on a passive avoidance conditioned reflex in rats.

Quinolinic acid, an endogenous neurotoxin, was introduced into the cerebral ventricles of a rat in doses of 0.5 microgram and 30 micrograms. The influence of the substance on the reproduction of a passive avoidance conditioned reflex (CR) was evaluated. It was found that a small dose of the preparation decreases extinction, while a large dose disrupts the reproduction of a passive avoidance CR. The disruption of the reproduction of the skill was also observed after bilateral electrolytic destruction of the dorsal hippocampus. Quinolinic degeneration of this structure exerted a substantial influence on the reproduction of a passive avoidance CR.

Animals↗
PubMedDate not supplied

Interactions between neurons in the amygdala and hypothalamus during conditioned reflex behavior involving choice of reinforcement quality in cats.

The organization of distributed amygdalo-hypothalamic and local amygdalar and hypothalamic neural networks was studied in three cats, trained to perform a food-related operant conditioned reflex to light by the "active choice" of reinforcement quality method; pressing the pedal with a short latent period provided the cats with a bread/meat mixture, while pressing with a long latent period yielded meat. Animals showed sharp differences in their individual abilities to choose one or the other reinforcement. Two cats preferred long-latency pedal-pressing to obtain meat, and were considered to be "self-controlled," while the third cat, which preferred short-latency pedal-pressing to obtain the less valuable reinforcement (the bread/meat mixture) was described as "impulsive." Chronically implanted semimicroelectrodes were used to record multineuron activity in the basolateral nucleus of the amygdala and the lateral nucleus of the hypothalamus. Interactions between the discharge trains of neighboring and distant neurons were assessed by cross-correlation analysis. Interneuron functional connections were found to predominate significantly in the local neural networks of the basolateral amygdala and distributed amygdalar-hypothalamic networks in the "impulsive" animal as compared with the "self-controlled" animals, suggesting a role for these types of connection in forming the individual characteristics of higher nervous activity. The identical incidences of interneuron interactions in the lateral nucleus of the hypothalamus in cats with different individual preferences suggest that local networks in this formation are not involved in analyzing reinforcement quality.

Amygdala↗
PubMed2001

Exercise-induced neuromuscular dysfunction under reflex conditions.

The purpose of this research was to describe further the effects of exercise-induced muscle damage on reflex sensitivity. The subjects were eight physically active, but untrained males, between the ages of 18 and 29 years. The effects of eccentric and concentric exercise on patellar tendon reflex responses were determined. The 8 week experiment consisted of two, 5 day, test protocols with a 6 week wash-out period between test protocols. Each 5 day test protocol consisted of the following six test sessions: (1) day 1--baseline, (2) day 2 baseline, (3) day 2--immediate post-exercise, and (4-6) days 3-5: 24, 48, and 72 h post-exercise. On day 2, the subjects made either 100 fatiguing concentric or eccentric isotonic contractions using the right leg at 75% of the corresponding repetition maximum values. During each test session, the electromyogram (EMG) and force-time characteristics of basic and conditioned patellar tendon reflex responses were measured. The reflex amplitudes of basic and conditioned patellar tendon reflex responses were decreased following fatiguing concentric exercise. There were no immediate effects of fatiguing eccentric exercise on the basic and conditioned patellar tendon reflex responses, but the EMG amplitudes of these reflex responses were reduced on the days following eccentric exercise. The amount of conditioned patellar tendon reflex facilitation was decreased following the concentric exercise protocol and at 48 h post-eccentric exercise. Our conditioned reflex data suggest that post-exercise changes to the physiological mechanisms that modulate the recruitment gain of the alpha-motoneuron pool may depend upon the type of fatiguing exercise.

Adolescent↗
PubMedDate not supplied

[Conditioned reflex changes in the intra-analyzer interaction of the afferent inputs from the lateral geniculate body and pulvinar thalami in the cerebral cortex of cats].

Paired heterogeneous stimulation of the lateral geniculate body (LGB) and pulvinar (Pulv) as a conditioned stimulus of alimentary instrumental conditioned reflex (CR), resulted in a change of relations between afferent inputs from LGB and Pulv to the visual and associative cortex of cats. At stimulation of LGB preceding by 40 ms, facilitation of the response to testing Pulv stimulation observed in untrained cats, appeared only at the beginning of the learning and was suppressed by the end of elaboration, when the amplitude of the response to the conditioning LGB stimulation greatly increased. In the process of CR elaboration (in the middle of learning), Pulv stimulation preceding by 40 ms facilitated the response to the testing LGB stimulation and simultaneously increased the amplitude of the response to the conditioning Pulv stimulation.

Afferent Pathways↗
PubMed1982

[Role of enkephalin-reactive system of the caudate nucleus in acquisition of alimentary conditioned reflex in dogs].

Bilateral injections of 15 and 45 mcg of synthetic analogue of TYR-D-ALA-LEY-Enkefaline-ARG into the body of the caudate nuclei in dogs produced a manifested increase in parameters of Pavlovian alimentary conditioned reflexes. Moreover, the dose of 15 mcg of LEY-enkefaline enhanced the background salivation and prolonged food consumption. Excited dogs became calm. During analogous injections into the right lateral hypothalamus the effect diminished while injections of 15 mcg of morphine hydrochloride were ineffective. The data point to role of the enkefaline-containing system in alimentary behaviour.

Animals↗
PubMedDate not supplied

[Importance of traces of a preceding unreinforced stimulus to the formation of inhibitory conditioned reflexes in the rat].

The results of experiments with the inhibitory signal presented to rats after the positive one, showed the significance of the negative signal memory trace which interrupted alimentary behaviour and considerably accelerated its full extinction in response to the previously positive signal. Its significance is shown in experiments with amnesia produced by electroshock. According to the suggested concept negative conditioned reflexes are a result of formation of a temporary connection between memory traces of the negative conditioned signal and the non-reinforcement of this signal.

Animals↗
PubMedDate not supplied

[Changes in the activity and conditioned-reflex behavior of white rats during and after chronic microwave irradiation].

Albino rats were exposed to chronic (1-3 months) electromagnetic radiation (2375 MHz; 1, 5, 10, 50 and 500 microW/cm2; 7 hours a day). Inhibition of the activity during the open field tests and diminution of consolidation of the defence conditioned reflexes in a shuttle chamber occurred during exposure (5 to 500 microW/cm2) while the activity increased and reflexes consolidation gradually normalized during the post-irradiation period.

Animals↗
PubMedDate not supplied

Effects of microinjection of scopolamine into the neostriatum of rats on performance of a food conditioned reflex at different levels of fixation.

Chronic experiments performed on 32 Sprague-Dawley rats using a movement-feeding operant reflex (Skinner box) model showed that microinjection of scopolamine into the neostriatum had effects on this reflex which depended on the stage of learning. In animals with weakly fixed reflexes (prior to reaching the stage of memory consolidation), bilateral microinjection of 0.3 microgram of scopolamine into the caudate nucleus completely inhibited the reflex for a prolonged period of time. When the operant habit was well fixed, bilateral microinjection of the same doses of scopolamine into the neostriatum had no effect on the reflex. These results suggest that the neostriatum cholinergic system is critically involved in forming the motor engram. The cholinergic system of the caudate nucleus either takes no part in realizing the well-fixed conditioned reflex movement response and/or other forebrain structures are involved in the reflex, compensating for the disturbance in neostriatal cholinergic function.

Animals↗
PubMedDate not supplied

[Restoration of the process of elaborating a conditioned reflex to light in rabbits following early visual deprivation].

Rabbits with a long period of visual deprivation (up to eight weeks since birth), unlike those with four-week deprivation, require a longer time period (over 30 days) to normalize elaboration of conditioned reflexes and to manifest their electrographic correlates (evoked potentials). The results obtained testify to the ability of recovering CNS functions disturbed by deprivation. It has been suggested that natural early training of the synaptic structures of specific neurones in the visual cortex play a decisive role in this phenomenon.

Animals↗
PubMedDate not supplied

Influence of neurohypophyseal peptides on the formation of active avoidance conditioned reflex behavior.

The role of lysine-vasopressin and oxytocin, as well as of their analog and fragment (DGAVP, desglycinamide arginine vasopressin; PLG, prolyl-leucyl-glycyl-amine), microinjected into the ventral hippocampus, in the formation and extinction of active avoidance conditioned reflex, was investigated. It was established that the introduction of lysine-vasopressin, as well as of its analog, into the hippocampus promoted the improvement of the formation of the avoidance reaction, while an inhibitory effect was elicited in the period of extinction of the skill. The opposite effects on the active avoidance reaction were obtained with oxytocin and its fragments. It is hypothesized that the observed behavioral changes in the active avoidance reaction are associated with the influence of these peptides on the processes of learning and memory.

Amino Acid Sequence↗
PubMed1979

[Changes in the ultrastructure and protein fractions of the cortex of the motor and visual analyzers during conditioned reflex avoidance reactions].

In avoidance conditioning, rats developed changes in the range of electrophoretic proteins as well as subcellular reconstructions in neurons and synapses which enabled them to fulfill specific functions on the basis of genetically fixed biochemical processes and ultrastructures. This corroborates ideas of information storage in the c. n. s. on the basis of formation of certain neuronal ensembles by means of changes in neurons' synapses facilitating the conduction.

Animals↗