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Results for “CONDITIONED REFLEX”

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PubMedDate not supplied

[Formation of chain reaction conditioned reflexes in chickens during different age periods].

The dynamics and mechanism of elaboration of chain instrumental reflexes were investigated in chicks at ontogenesis. It has been established that the older the chicks, the higher the rate of chains synthesis and the longer their preservation. The synthesis of chain conditioned reflexes has been observed since the age of two months, when the inhibitory process, concentration and equilibration of nervous processes are strengthened. The synthesis mechansims of motor reactions are similar in the birds of different ages: at first, the connections of each component of the chain stimulus with the motor reaction are elaborated, then they are replaced by successive connections between the first component of the chain and the whole chain of elaborated reactions. Long training of the chain reflex leads to the development of retardation inhibition and the appearance of a motor reaction to the last component of the chain reflex.

Age Factors↗
PubMed2004

Acetylcholine release in the hippocampus during the operant conditioned reflex and the footshock stimulus in rats.

The activity of the septo-hippocampal cholinergic pathway was investigated by measuring changes in the extracellular acetylcholine (ACh) levels in the hippocampus, by means of microdialysis, during the operant conditioned reflex and the repeated footshock stimulus. Microdialysis samplings were conducted in a Skinner box where lights were delivered as conditioned stimuli (CS) paired with footshocks as unconditioned stimuli (US). Two groups of rats were used. Extracellular ACh and choline (Ch) in samples collected at 6min intervals were assessed by high-performance liquid chromatography with electrochemical detection. The elevation of hippocampus ACh was observed in the two experimental groups. The increase in ACh during aversive stimulus (footshock) was significantly larger and was probably related to the number of footshocks. There might be moderate increase in the hippocampal ACh release during the retrieval of information. The concentration of choline showed no significant fluctuation in the two groups during the whole process. This experiment explored in more detail hippocampal cholinergic activity in relation to the two different procedures.

Acetylcholine↗
PubMed1979

[Changes in active 14C-noradrenaline uptake by cerebral synaptosomes during elaboration of a conditioned reflex].

It was shown that active noradrenaline-14C (NA) uptake by the rat brain synaptosomes is inhibited by ouabain (0.1 M) and K-depolarization. Acquisition of the defensive conditioned reflex leads to inhibition of active NA uptake by the synaptosomes. This effect may be connected both with changes in the presynaptic membrane state and possible enhancement of the postsynaptic adrenoreceptor function.

Absorption↗
PubMed1981

[Binding of 3H-diazepam by cerebral cortex synaptic membranes in the rat during conditioned reflex elaboration].

In-vitro experiments were made to compare specific binding of 3H-diazepam with synaptic membranes obtained from the large hemispheres of rats trained the defense conditioned reflex to that in rats exposed to non-combined stimuli (active control). Within the concentration range of 0.37 nM-30 nM, specific binding of 3H-diazepam with the synaptic membranes obtained from the brain of active control animals was considerably higher than that with the synaptic membranes obtained from the trained animals brain.

Animals↗
PubMedDate not supplied

[The role of the lateral and medial hypothalamus in reproducing a motor reaction as the signal during the acquisition of classical conditioned reflexes].

In experiments on three dogs there was shown that testing electrostimulation of the lateral hypothalamus reproduced the motor reaction which is a signal stimulus at elaboration of classic alimentary conditioned reflexes (CRs) and did not reproduce it at elaboration of classic defensive CR. Testing electrostimulation of medial parts of the hypothalamus reproduced, as LH electrostimulation the "signal" motor reaction, but in less percentage of cases, during elaboration of classic alimentary CRs and did not reproduce it at elaboration of classic defensive CRs. The reproduction of the signal motor reaction at LH electrostimulation is connected with activation of backward conditioned connection from motivation structures of the hypothalamus to representation of the signal stimulus in the motor cortex.

Animals↗
PubMedDate not supplied

[Changes in the complex conditioned reflex activity of rat pups under the influence of penta-peptide].

Influence of YFRKD, modified fragment of interferon-alpha, on the formation of two-links system of feed-procuring conditioned reflexes was studied in rats in ontogenesis. The experiments have shown that YFRKD impedes both current learning and use of previous experience. The process of synthesis of two reflexes in united complicated functional complex is disturbed.

Animals↗
PubMedDate not supplied

[Conjugation of unit activity in the visual and sensomotor areas of the rabbit neocortex during a conditioned reflex to sound and light].

Conjugation of unit activity in the visual and sensorimotor neocortical areas was studied by means of histograms of cross- and autocorrelation in rabbits with conditioned reflex to light (1st group) and sound (2nd group). Relative number of neurones pairs acting in correlation in the areas remote from each other, in intersignal intervals both before and after stimuli did not differ in the 1st and 2nd groups. At the same time delays in neuronal discharges in one area after the other were different. In the 1st group animals there was a predominance of the number of visual area neurones discharging after sensorimotor with a delay up to 125 ms, in comparison with the number of sensorimotor area neurones discharging after the visual one. In the 2nd group rabbits the number of visual area neurones with such a delay of discharges after sensorimotor was less and, on the contrary, a predominance of sensorimotor area neurones was observed discharging after the visual one. The obtained results allow to suggest that neurones of the visual and sensorimotor neocortex areas form a single functional system in cases when conditioned and unconditioned stimuli are addressed to these areas and when only one of the studied areas is the projection zone for the combined stimuli. Organization of the neurones activity in systems in these two cases is different.

Animals↗
PubMedDate not supplied

The participation of pharyngo-oesophageal thermoreception in the formation of water-reinforced instrumental conditioned reflex.

In 79 rats with chronically implanted gastric tubes or thermodes the participation of pharyngo-oesophageal thermoreception was investigated in the process of development of a water-reinforced conditioned instrumental reflex. It was found that only cooling of the pharynx and oesophagus was an effective stimulus reinforcing instrumental conditioning. The conditioned reflex could not be developed when the reinforcing stimulus was the sensation of warmth in the throat and oesophagus, and gastrointestinal interoception. It is suggested in the discussion that cold thermoreception in the area of the throat and oesophagus has acquired its reinforcing character through conditioning.

Animals↗
PubMed1979

[Characteristics of the neuronal responses of the auditory zone of the cortex of awake cats in the resting state and during an elaborated defensive conditioned reflex].

The responses of 288 neurons with background activity in the first auditory cortex were investigated using glass microelectrodes in chronic experiments on cats at rest (123 neurons) and during elaboration of a defensive conditioned reflex to sound stimulation (165 neurons). At rest 43% of recorded neurons did not respond to the sound stimulus. Pronounced inhibition of background activity prevailed among responding neurons (about 60%). The conditioning caused an increase (to 72%) in proportion of neurons responsive to the sound stimulus, appearance of tonic reactions, as well as an increase in frequency of bursts and in proportion of activation type responses. It is suggested that these changes indicate the enhancement of neurons excitability in the zone under study during conditioning.

Animals↗
PubMedDate not supplied

Conditioned reflex responses of the sympathetico-adrenal system to an aversive taste stimulus.

Studies were carried out on male and female rats in which the effects of isolated presentation of a conditioned stimulus (a saccharine solution) to which the animals had previously developed conditioned reflex taste aversion (RTA) on the level of urinary catecholamine secretion were determined. The studies showed that presentation of an aversive taste stimulus without reinforcement by a negative stimulus increased the levels of urinary adrenaline, noradrenaline, and dopamine secretion; this repeated, albeit more weakly, the effects of the negative reinforcement (angular acceleration) used for development of RTA. After presentation of the isolated aversive taste stimulus, the greatest increase in catecholamine excretion affected adrenaline, which indicates an anxiety state (fear). There was also a significant increase in noradrenaline excretion in these conditions. The accompanying increase in dopamine excretion in experimental and control animals showed this change to be largely nonspecific in nature, and to result from the experimental procedures. Isolated presentation of the conditioned taste stimulus elicited significantly greater increases in urinary catecholamine excretion in males than in females. It is suggested that the time for which the RTA is retained could be increased by activation of the sympathetico-adrenal system resulting from presentation of the nonreinforced taste stimulus which had acquired aversive properties.

Adrenal Glands↗
PubMed1989

[Effect of a cyclic enkephalin analog on the protein content in the hippocampal neurons of rats during the acquisition of a 2-way avoidance conditioned reflex].

The protein content has been determined by means of cytointerferometry in neurons of fields CA-1 and CA-3 of the dorsal hippocampus in rats, which were trained in a conditioned reflex of two-way avoidance (CRTA) with the action of subcutaneously injected enkephalin cyclic analogue (ECA) in a dose 10 mkg. It has been found that after ECA injection the protein content in the neuronal nuclei of the hippocampal CA-3 field reduces. The acceleration of the CRTA elaboration occurring during the action of ECA is accompanied by a drastic increase of the protein content in the neuronal nuclei of the CA-3 field. The ECA administration to the rats of the active control groups to which were presented the same number of unpaired conditioned and unconditioned stimuli as during the CRTA elaboration also enhances the protein content in the neurons of the CA-3 field. The rats of all investigated groups in the neurons of the CA-1 field display no such significant shifts. The conclusion has been drawn that ECA produces a regulating influence on protein metabolism in hippocampal neurons depending on their functional state.

Animals↗
PubMedDate not supplied

[Role of functional asymmetry of the cerebral hemispheres in organization of an instrumental alimentary conditioned reflex in cats].

During instrumental alimentary conditioning in cats the speed of reflex stabilization depended on the correspondence between the dominant leg's lateralization and the side of the lever, which the animal had to press in response to the signal. When the lever was on the side of the dominant leg, the speed of the conditioning was greater than in the absence of such correspondence. Functional switching off (KCl) of the cortex of any hemisphere at the stage of reflex stabilization does not disturb the instrumental reaction. The switching off of the dominant hemisphere at the stage of stable reflex disturb the instrumental reaction, but has no effect on more simple forms of conditioned behaviour, e. g. run to the feeding through in response to the signal.

Animals↗
PubMed1996

[From Pavlov's recording of time and conditioned reflexes to the chronophysiology of human nutrition].

That I. P. Pavlov understood how important to record the time factor allowed him to anticipate the chronobiological approach in physiology. As compared to the conditioned reflexes, the body's biological rhythms appeared to have a deeper basis - chronomes coded in the genes. The authors comparatively characterize the homeostatic approach used by I. P. Pavlov and the chronobiological approach proposed by F. Halberg both for biology and medicine.

Animals↗