Biomedical subjects

Zh A Kruchenko

Publications and source records attributed to Zh A Kruchenko.

13 recordsLinked to original sources

PubMed2006

[Genetically determined characteristics of conditioned reflex and locomotor activity of rats of different lines].

Peculiarities of conditioned instrumental food obtaining (getting) "pyrocmu" reflex development and realization of locomotor reactions (exploratory activity, motor activity, stance, gruming) of hypertensive (SHR) and Wistar rats in ordinary conditions and after strong sound signal were studied. It is shown that the dynamics of conditioned reflex development and its reproducing after experiment interruption are essentially different in two groups of animals: reflex conditioned in Wistar rats is of high level and is easily reproducible while in hypertensive animals it is transformed to the hidden (concealed) form of "incomplete" conditioned reflex-smelling at feeding rack in response to sound signal. The higher anxiety level and lower adaptability of hypertensive rats as compared with Wistar rats to the experimental conditions are confirmed by higher exploratory activity, more prolonged gruming in standard experimental conditions and long-duration immobility phase after sound signal.

Acoustic Stimulation↗

PubMed1990

[The effect of the selective blocking of synaptic transmission in the parafascicular complex on the neuronal activity of the sensorimotor cortex].

Peculiarities of spike responses of the sensorimotor cortex neurons and conditional activity induced by blockade of noradrenergic and serotoninergic inputs of the PF complex (CM-PF) have been studied in chronic experiments on cats with a preliminarily conditioned placing reaction to an auditory stimulus--a click. It is shown that an increase in the background activity of neurons of the sensorimotor cortex was caused by microinjections of obsidan, an adrenergic blocker, while depression--by microinjections of lysergoamid, a serotonin blocker. The effect of both blockers on the neuronal reactions evoked by conditional auditory stimulus was the same (depression). Both conditional placing and unconditional one were removed by partial blockade of monoaminergic inputs for 30-60 min. A conclusion is made that the character of the influence of the monoaminergic system on the sensorimotor cortex is determined not only by direct, but also by indirect influences due to neurons of the CM-PF complex of thalamic nuclei.

Acoustic Stimulation↗

PubMed1986

[Participation of neurons of the midbrain reticular formation of the cat in conditioned reflex activity].

Spike discharges of mesencephalic reticular formation neurons were investigated during classical and instrumental conditional reflexes in chronic experiments on cats. Neurons were divided into several functional groups according to patterns of their responses. Two groups of neurons produced continuous tonic spike discharges. One of them was activated by positive conditional stimuli and did not respond to the same stimulus after extinction. Another group was involved in reaction only after extinction. Thus the neurons of these two groups developed additional tonic ascending action not only during fulfillment of conditional reflex but under its internal inhibition too. Neurons of the third group revealed double phasic responses: the first--to sound and the second--in connection with initiation of the conditioned movement. They decreased the level of the background and evoked activity during differentiation and extinction. Initial changes of reticular neuron responses were similar under conditioning and under pseudoconditioning. It is concluded that mesencephalic reticular formation takes an active and differential participation in elaboration, fulfillment and internal inhibition of classical and instrumental conditional reflexes.

Animals↗

PubMed1977

[Responses of neurons in the secondary somatosensory zone of the cat cortex during elaboration of a defensive conditioned reflex].

The neuronal responses of the somatosensory secondary cortex during the process of formation and extinction of a conditioned defence reflex to sound stimulus were studied in chronic experimentss on cats. In 21 out of 28 examined neurons a change in activity took place during the formation of a conditioned reflex as a response to the conditional signal. Two types of conditioned reflex responses were observed: excitatory and inhibitory ones. Most of the neurons excited by the conditioned stimulus responded during the first 50 ms, preceding the conditioned movement by 80-100 ms. Significant variability of neuronal responses was observed during formation of the conditioned reflex. After stabilization the neuronal responses to the conditioned stimulus acquired a stable from. During extinction of the neuronal conditioned activity a decrease of the discharge frequency in the excitatory neuronal response and disinhibition of the activity in the inhibitory responses were found.

Animals↗

PubMed1977

[Reactions of neurons of the secondary somatosensory cortex of awake cats to electrocutaneous and acoustic stimulation].

In chronic experiments on alert cats the discharges of neurons in the secondary projection zone of the somato-sensory cortex to click and electrical stimulation of contralateral paw were investigated. 57% of neurons responded to "specific" stimulation by increasing the discharge frequency, 18%--by weakening or stopping the background activity, while 25% did not react at all. 30% of neurons responded by activation to the "non-specific" stimulation (click), 25%--by inhibition and 45% were unresponsive. An investigation of intersensory convergence by sending signals from different analyzer systems showed that bimodal responses are peculiar to most neurons (55%) of this zone. 18% of neurons with a response only to the "specific" or "non-specific" stimuli were found. It is suggested that polysensory convergence on the neurones of the somato-sensory cortex is important for the cortical area in the process of closing of conditioned connections.

Animals↗

PubMedDate not supplied

[Neuronal activity of the cerebral cortex in cats with conditioned inhibition].

Unit activity of the somatosensory cortex was studied in chronic experiments on cats during alimentary instrumental conditioned reflex performance and elaboration of conditioned inhibition (CI). First presentations of the CI signal at the beginning of CI formation caused, due to orienting reaction to a new stimulus, a levelling of the response of the neurones to the positive conditioned signal included into the CI complex. At the stage of consolidated CI, this depression proceeded gradually during the development of conditioned inhibition caused by consecutive presentations of the nonreinforced CI combination. Two groups of neurones were involved in the process of the CI performance: one of them being the same which was activated also in response to positive stimulation during performance of the conditioned response, and the second one being areactive to the positive conditioned stimulus but reducing the frequency of the background activity.

Animals↗

PubMedDate not supplied