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Results for “CONDITIONED REFLEX”

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PubMedDate not supplied

[Slow potentials of the prefrontal cortex in dogs and the classical secretory conditioned reflex].

Slow potentials (CNV and component P300) were recorded in the medial part of the prefrontal cortex of dogs trained to classical secretory conditioned reflex and its differentiation. CNV increased when the conditioned stimulus was preceded by a signal of different meaning, as compared with CNV to the same conditioned signal following the stimulus of the same meaning; the greatest values of CNV and P300 were observed in response to differential stimulus preceded by a positive signal.

Acoustic Stimulation↗
PubMedDate not supplied

[Conditioned reflex activity in the aging process in white rats].

In Wistar rats, irrespectively of their age, conditioned reflexes to present stimuli are preserved and elaborated. Neither the mechanism of time intervals estimation is disturbed in aged and old rats (24-32 months). Long intervals between experiments (3-5 months) do not influence their state. Distinct changes are revealed of spatial-temporal differentiations in T-maze: significant worsening of their state is observed in 8-10 months age; in this age it is neither possible to elaborate them again. In simplified experimental conditions in the T-maze the old rats preserve the spatial orientation.

Acoustic Stimulation↗
PubMed1978

Reflex conditioning in a spinal man.

A man with a completely transected spinal cord and a spastic neurogenic bladder was conditioned to void upon the presentation of an external stimulus. A classical conditioning paradigm was employed in which strong abdominal shock (unconditioned stimulus) was paired with an initially neutral mild electrical stimulation of the thigh (conditioned stimulus; CS). After the pairing trials, a reliable conditioned response of urination was elicited by the CS alone. The conditioned response did not extinguish over time, and the procedure left the bladder with clinically safe residual amounts of urine. Practical implications of the conditioning technique for the treatment of spastic neurogenic bladder conditions in spinally injured patients are discussed, as is the theoretical significance of conditioning at the reflex level in the absence of cortical involvement.

Abdominal Muscles↗
PubMedDate not supplied

[Neuronal activity of the head of the caudate nucleus during formation of positive and inhibitory motor alimentary conditioned reflexes in cats].

Cellular activity of the caudate nucleus head was studied on 15 cats during motor alimentary conditioning, extinction and elaboration of differentiation response. Analysis of the dynamics of the appearance and stabilization of neuronal conditioned responses attests that the caudate nuclei are a part of the morpho-functional structure of the given conditioned reflex. A functional heterogeneity within the nuclels head has been shown on the basis of responses of the cells during conditioned and unconditioned behaviour. It has been assumed that cellular populations of the ventral segment of the caudate nucleus head are predominantly involved in providing for a normal course of the processes of extinction and detection of significant signals in this form of conditioned alimentary behaviour in cats.

Animals↗
PubMedDate not supplied

[Typological characteristics of conditioned reflex learning in monkeys].

Three types of conditioned learning dynamics were singled out in males of the rhesus monkeys by the speed of formation of a positive motor instrumental reflex and differentiation. Type I is characterized by the fastest mastering of separate subprograms and of the whole test program of conditioned behaviour, by optimal functional characteristics in the process of learning and by a high adaptivity in new conditions. The most prolonged formation of the conditioned reflexes occurs in monkeys of the III-d type; 50% of them do not master the whole learning program; monkeys with such type of learning dynamics have no adaptation of previously acquired conditioned stereotype to new environmental conditions. Monkeys of the II-nd type of learning dynamics possess intermediate characteristics. A notion is substantiated of interconnection of higher nervous activity properties with typological characteristics of conditioned learning dynamics in monkeys.

Adaptation, Psychological↗
PubMedDate not supplied

The effect of L-tryptophan on conditioned reflex learning and behavior in rats with experimental pathology of the thyroid gland.

The effects of L-tryptophan on conditioned reflex learning and behavior were studied in male rats with deficient and excess thyroid hormones levels. The learning process was studied using a model consisting of a conditioned active avoidance response; animal behavior was assessed in an open field test. These studies showed that in conditions of thyroid hormone deficiency. L-tryptophan had positive effects on the acquisition and reproduction of the active avoidance reflex, restoring the ability of the animals to learn actively; L-tryptophan increased investigative activity in the open field test. In conditions of increased thyroid hormone levels, L-tryptophan reversed the mild stimulating effects of thyroid hormones on the processes of developing and performing the active avoidance habit, and increased investigative activity, but decreased the amount of grooming.

Animals↗
PubMedDate not supplied

[Formation of combined stereotypes of systems of secretory conditioned reflexes].

A rhythmic stereotype, followed by a rhythmic-mozaic one of positive and inhibitory conditioned secretory reflexes were successively elaborated in dogs with stabile stereotype of three heteromodal randomely organized systems. Thus a combined stereotype was formed of five randomely and stereotypically organized systems of conditioned reflexes, achieved at intervals of 24 hours or longer in a regular sequence. It has been shown that in the course of formation of the combined stereotype the general functional state (tone) of the cerebral cortex is enhanced. The preliminarily formed specialized systemic nervous process with a similar structure is of major importance for the rate of formation of the complex rhythmic-mozaic stereotype.

Animals↗
PubMed1988

[Action of cortical extracts of the left and right hemispheres on the recovery of conditioned reflex activity in rats after unilateral removal of the frontal cortex].

The recovery of active avoidance conditioned reflex (AACR) was investigated after unilateral frontal cortex extirpation. Intraperitoneal injection of extracts from left or right brain cortex (1 mg/kg) of healthy rats (LE or RE) stimulated AACR recovery in animals with lobectomy on the same side. If RE was extracted 9 days after left side brain extirpation, i.e. during the period of the development of compensatory processes, its effect on AACR recovery was stronger in left-operated animals, while in right-operated animals it remained unchanged.

Animals↗
PubMed1979

[Dynamics of neuronal responses of the auditory zone of the cortex of wakeful cats during the process of elaboration of a defensive conditioned reflex to acoustic stimulation].

In chronic experiments on cats the neuronal responses (recording by means of glass microelectrodes) of auditory cortex I were studied during elaboration of a defensive conditioned reflex to a sound stimulus. During conditioning the biphasic reactions with a rather short-latent (50-100 ms) and more long-latent (400-500 and 800-900 ms) activation were predominant. The neighbouring neurons whose responses were recorded by the same microelectrode were involved into the activity more intensively. A differentiating stimulus in 70% of applications caused distinct changes in neuronal activity (predominantly of activation type). Analysis of the dynamics of responses of the same neuron during a great deal of combinations and its comparison with the formation of a motor reaction showed no direct correlation between the two events.

Animals↗
PubMedDate not supplied

[Features of the formation and retention of a motor-defensive conditioned reflex in rats of various strains].

Comparison of the dynamics of elaboration and stabilization of a motor defensive conditioned reflex in rats of Wistar line and in grey rats showed that the latter significantly forestalled the white laboratory rats in the speed of conditioning. Their behaviour was characterized by a higher level of excitability and activity and a weaker passive defensive behaviour; this probably contributed to a more effective formation of temporary connection with biologically negative reinforcement. Individual typological differences did not conceal the interlinear ones, while in stress situations they can sometimes be at the foreground.

Animals↗
PubMed1985

Retention of a classically conditioned reflex response in spinal cat.

Retention of classically conditioned flexion reflex facilitation was examined in unanesthetized, decerebrate, acute spinal cats. Flexion reflex facilitation, recorded from the tibialis anterior muscle, was obtained by pairing saphenous nerve stimulation (the conditioned stimulus) with superficial peroneal nerve stimulation (the unconditioned stimulus). The flexion reflex declined in control animals receiving the same number of nerve stimuli over the same time span, but in an explicitly unpaired sequence. To investigate retention, conditioned stimuli were presented at 5-min intervals following acquisition for a 2 1/2-h period. During this time a significant difference between conditioning and control groups was maintained even to the last trial, with no indication that the difference was subsiding over time. The results support the possibility that a classical conditioning paradigm applied to the spinal cord can induce alterations in spinal reflexes of long duration. Furthermore, the results appear to rule out post-tetanic potentiation as a mechanism producing the observed long-term effects.

Animals↗
PubMed1976

Excitability of human motoneurones after discharge in a conditioning reflex.

A new method of exploring the H reflex excitability cycle is proposed which permits the exploration of motoneurones that discharged in response to the conditioning shock. This is made possible by using a test stimulus supramaximal for the alpha motor fibres of the nerve, which causes a collision in the alpha fibres between the orthodromic conditioning reflex volley and the antidromic motor volley. As a result of this collision, a test reflex contraction appears in the EMG, due to motoneurones that have already discharged in the conditioning response. This method permits studies in human subjects of the poststimulus refractory period of motoneurones as well as the early inhibitory phenomena related to the conditioning stimulus and response. It is shown that during the initial period of the classical H reflex excitability cycle, the test shock explores only alpha motoneurones corresponding to a fringe of cells subliminally excited by the conditioning stimulus. The difference between the populations of motoneurones tested by the two methods explains the differences between the features of the cycles obtained.

Evoked Potentials↗
PubMedDate not supplied

[The effect of mixtures of caffeine, glucose and ascorbic acid on conditioned reflex activity in dogs during the postanesthetic period].

It was shown in experiments on four dogs by the conditioned method that the period of recovery of conditioned activity after one hour ether anaesthesia tested 7 to 7.5 days. Premedication with a mixture of caffeine, glucose and ascorbic acid reduced the recovery time to four or five days. After the administration of the complex in the postanaesthetic period (in 2.5 hours after anaesthesia) the stabilizing effect was still more pronounced. Thus, the recovery time of unconditioned and conditioned reflexes and differentiation was reduced to three or four days.

Anesthesia, General↗
PubMedDate not supplied

The cerebellum in maintenance of a motor skill: a hierarchy of brain and spinal cord plasticity underlies H-reflex conditioning.

Operant conditioning of the H-reflex, the electrical analog of the spinal stretch reflex, is a simple model of skill acquisition and involves plasticity in the spinal cord. Previous work showed that the cerebellum is essential for down-conditioning the H-reflex. This study asks whether the cerebellum is also essential for maintaining down-conditioning. After rats decreased the soleus H-reflex over 50 d in response to the down-conditioning protocol, the cerebellar output nuclei dentate and interpositus (DIN) were ablated, and down-conditioning continued for 50-100 more days. In naive (i.e., unconditioned) rats, DIN ablation itself has no significant long-term effect on H-reflex size. During down-conditioning prior to DIN ablation, eight Sprague-Dawley rats decreased the H-reflex to 57% (+/-4 SEM) of control. It rose after ablation, stabilizing within 2 d at about 75% and remaining there until approximately 40 d after ablation. It then rose to approximately 130%, where it remained through the end of study 100 d after ablation. Thus, DIN ablation in down-conditioned rats caused an immediate increase and a delayed increase in the H-reflex. The final result was an H-reflex significantly larger than that prior to down-conditioning. Combined with previous work, these remarkable results suggest that the spinal cord plasticity directly responsible for down-conditioning, which survives only 5-10 d on its own, is maintained by supraspinal plasticity that survives approximately 40 d after loss of cerebellar output. Thus, H-reflex conditioning seems to depend on a hierarchy of brain and spinal cord plasticity to which the cerebellum makes an essential contribution.

Animals↗
PubMed1991

[Spike reactions of neurons of the cat thalamic reticular nucleus during elaboration of an instrumental conditioned reflex].

Spike reactions of 156 neurons of the thalamic reticular nucleus (R) have been studied during performance of instrumental alimentary conditioned reflex. These reactions consist of initial and late phases. The latencies of initial reaction phase are 10-100 ms and duration--50-250 ms. The minimum data of late phase latencies are 100-300 ms. Initial responses to the conditional sound click are found in 27 neurons: 26 of them show excitation and one neuron--inhibitory-excitatory responses. The late reaction phase has been observed in 134 neurons only during performance of conditioned placing reactions: 115 of them show excitation, 19 neurons--inhibition and 22 neurons--were not reactive. Responses of 30 neurons forestalled the performance of conditioned forelimb movement. 118 neurons responded during the ballistic phase of the movement. It is concluded that the thalamic reticular nucleus takes part in the conditional signal perception and in the preparation and control of conditioned movement performance.

Action Potentials↗
PubMed2003

Analysis of glucose and lactate in hippocampal dialysates of rats during the operant conditioned reflex using microdialysis.

Changes of extracellular glucose and lactate in hippocampus for freely moving rats during the operant conditioned reflex were examined simultaneously. Samples of the dialysate were assayed for both glucose and lactate using in vivo microdialysis and a microbore flow injection analysis-immobilized enzyme reactor-electrochemical detection (FIA-IMER-ECD) system. Microdialysis samplings were conducted in a Skinner box where lights were delivered as conditioned stimuli (CS) paired with foot shocks as unconditioned stimuli (US). In the treatment group the concentration of glucose and lactate showed no fluctuations during the whole process. However, in the control group in which the rats were exposed to many foot shocks, lactate levels decreased by 19% below baseline during the behavioral session and glucose showed a delayed decrease (by 18%). Compared with glucose, lactate can immediately indicate the dynamic changes in brain.

Animals↗