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PubMedDate not supplied

[Demonstration of afferent connections of the forebrain in Emys orbicularis turtles by the peroxidase method].

The transport of horseradish peroxidase (HRP) out of the injection site in the dorsal ventricular ridge was studied in turtles Emys orbicularis. Labeled cells in the forebrain were observed in the paleostriatum among fibers of the lateral forebrain bundle. In the thalamus most of cells containing the granular HRP reaction product were located in the n. rotundus, n. reuniens and perirotundal nuclei (n. dorso-medialis anterior, n. magnocellularis thalami, n (centralis) lateralis, n. dorso-medialis). Fewer labeled cells were revealed in the n. anterior and n. ventralis. The density of labeled cells in the majority of all thalamic nuclei increased if the HRP was extended from the dorsal ventricular ridge into the neostriatum and the pallial thickening with adjacent general cortex. HRP positive cells in the pretectal area, nuclei of the posterior commissura and mesencephalic ventro-lateral tegmentum were observed only in cases when the enzyme was diffused from the injection site into the neostriatum, while the HRP retrograde transport to n. geniculatus lateralis, pars dorsalis was revealed only when HRP was extended into the pallial thickening and adjacent general cortex. Ascending connections of the paleostriatum, thalamic nuclei and mesencephalic tegmentum with telencephalic structures, mainly with the dorsal ventricular ridge, were discussed.

Animals↗
PubMedDate not supplied

[Study of the ancient tecto-thalamo-cortical pathway of the visual system in rats].

Recording the evoked potentials and neuronal activity, electrophysiological studies have been made on tecto-thalamo-cortical tract in rats. The existence of a system of efferent projections in the superficial, visual layers of the superior colliculi was shown which are diffusely present in the nucleus lateralis posterior (n. LP), indicating low level of morpho-functional organization of this region of the dorsal thalamus in rats. In response to electrical stimulation of the n. LP, in laterocaudal parts of the visual system (fields 17 and 18a of the cortex) the evoked potentials of primary-negative polarity were observed which are associated mainly with the superficial (I--IV) cortical layers. Predominant representation of tecto-thalamo-cortical system in the laterocaudal visual area of the cortex indicates the tendency to separate representation (with respect to cortical areas and cortical layers) of retino-geniculate and retino-tecal visual systems in rats.

Animals↗
PubMedDate not supplied

[Electrophysiologic study of hippocampo-hypothalamic connections in rabbits].

Using the evoked potentials (EP) studies have been made on functional connections of different fields (CA1, CA3) of the dorsal hippocamp with phylogenetically different parts of the hypothalamus in rabbits. It was shown that during stimulation of both the field CA1 and the field CA3 of the hippocamp, the EP are widely present in nuclear structures of the posterior hypothalamus (supramammilary area, the posterior hypothalamic area, mammilary bodies). In the anterior hypothalamus (area preoptic medialis), the EP were recorded only during stimulation of the field CA1 in the dorsal hippocamp.

Animals↗
PubMedDate not supplied

Window panes of eternity. Health, disease, and inherited risk.

Personal health reflects harmony between individual and experience; it is optimal homeostasis. Disease is an outcome of incongruity leading to dishomeostasis. Relative to earlier times, disease in modern society has higher "heritability" (in the broad meaning of the term). Inherited risks are facts compatible with anticipation and prevention of disease. This viewpoint has major implications for medical practice, deployment of health services, themes of research, and education of health care personnel and citizens.

Aging↗
PubMedDate not supplied

[Interaction of forward and backward conditioned connections as the neurophysiologic basis of the motivation for behavior].

Motivation is defined as a physiological mechanism of activation of traces, kept in memory (engramms) of those external objects which can satisfy the organism's need and those actions which can satisfy it. In the last years E. A. Asratyan advanced and substantiated the concept that the physiological mechanism of motivation is based on the interaction of forward and backward conditioned connections where the backward connection is an activating influence of reinforcing reflex on the structures receiving conditioned signal and achieving the action which was earlier followed by reinforcement. It is experimentally shown that the appearance and extent of the backward conditioned connections generalization depend on the degree of motivational excitation. The backward conditioned connection is a specialized Ukchtomsky's dominant in the functional structure of the consolidated conditioned reflex, which makes the behaviour goaldirected and active. Thus, fundamental phenomena lay in the basis of behaviour: dominant and conditioned reflex--discovered and introduced in the science by A. A. Ukchtomsky and I. P. Pavlov. In the individual adaptive behaviour the dominant and conditioned reflex play the same role as variability and selection in the process of evolutionary adaptation. That is why the suggestion made by K. Popper and J. Eccles (1977) to replace Pavlov's theory of conditioned reflexes by the hypotheses theory is unfounded.

Adaptation, Psychological↗