Spatial organization of the lesser peritoneal sac during the early stages of human ontogeny

In 63 series of histological sections of human embryos and prefetuses (4-13 weeks) and in 30 corpses of fetuses and stillborns it has been stated that during the 4th week certain changes occur resulting in formation of the lesser peritoneal sac. It further develops into 3 sections: vestibulum bursae omentalis, bursa omentalis proper and cavity of the omentum majus. Spatial-temporal organization of the lesser peritoneal sac is neither connected with development of separate organs or structures, nor with independent growth, but with the process of development of the whole organocomplex of the upper part of the abdominal cavity, formation of topography and organs' fixation, growth peculiarities of the dorsal mesogastrium. The bursa omentalis proper is forming at the expense of retransformation of the hepatogastric pocket, dependent on growth of the dorsal mesogastrium and on a change in the stomach position. The vestibulum bursae omentalis appears in connection with development and formation of the liver topography, lesser omentum and duodenum. The right pulmoesophagial pocket is interrupted by a developing diaphragm with formation of the superior torsion of the bursa omentalis. Disorders in fixation processes of the organs in the superior part of the abdominal cavity and formation of the bursa omentalis topography can serve as a morphological prerequisite for cysts developing in the retroperitoneal space and hernias of the foramen epiploicum.     

Interrelations between globus pallidus and hippocampal epilepsy in the cat

Electrically induced afterdischarge (ADs) were evoked in the cats' dorsal hippocampus. The action of the conditioning prestimulation of the pallidus nucleus on AD duration was studied. A significant facilitatory influence was observed when pallidal conditioning stimulation immediately preceded hippocampal test stimulation. The time course of the phenomenon showed a decrease of the conditioning action when the interval between the two stimulations increased : complete disappearance of the effect occurred after about 800 ms. Results are discussed as far as functional relationships between basal ganglia and rhinencephalic system are concerned.     

The regulation of osmotic and ionic balance in fish reproduction and in the early stages of ontogeny

On the basis of the modern literature data we analyzed the influence of the level of salt concentration and ion composition in a fish habitat during the processes of reproduction. The results of studies of the mechanisms of the reaction of fish to gamete hypo- and hyperosmotic stimulus in the external aqueous environment, as well as the role of mineral and organic osmolytes in the adaptation of mature eggs of fishes in the external environment, depend on the hydrochemical and hydrological conditions of the spawning grounds. The paper provides information about the features of the endocrine regulation of oocyte maturation in fish spawning in different hydrological conditions and the importance of humoral factors in the pathological process of the maturation of fish oocytes. The main scientific and practical aspects of the formation of the phys mechanisms that regulate the water-salt balance is the early ontogeny of fishes are discussed.     

Cholinergic regulation of the activity of somatosensory cortex neurons during early postnatal ontogeny of the cat

In 11-14 days kittens, about 20% of neurones in the somatosensory cortical zone react to stimulation of subpallidal region which is a source of cholinergic projections to the cerebral cortex. The effect of subpallidal region stimulation is reproduced in case of microiontophoretic acetylcholine application and blocked by atropine what points to its cholinergic nature. Cholinergic stimulation causes inhibition of the background and evoked activities of the cortical neurones while, as it is known, in adult cats, acetylcholine mainly stimulates a reaction of activation. It is postulated that in kittens at the end of the second week of postnatal development, cholinergic innervation of the cortex significantly differs from the definitive one by its quantitative and functional parameters.     

Connections between the posterolateral nucleus of the thalamus and the parietal and occipital areas of the cerebral hemispheres in the cat

A light optic and electron microscopic investigation on distribution of fibers from the thalamic posterolateral nucleus has been performed in the cat cerebral cortex. The fibers studied are revealed in the fields 7, 19 and 18. In the field 7 they are most numerous, comparatively seldom they are found in the field 19 and still more seldom--in the field 18. In the fields 7 and 19 identical peculiarities on distribution and termination of the fibers are noted: they spread across the whole cortex and end in all the layers with a predominant concentration in the layers III and IV. Most of the fibers make contacts on small dendritic branches and spines. In the field 18 the fibers are mainly limited by the medial layers and terminate predominantly on small, middle-sized dendritic branches, and comparatively rare--on the spines.     

Compensatory processes in the motor cortex of the cerebral hemispheres in partial damage to the ventrolateral thalamic nucleus in the cat]

In cats alimentary instrumental reflex was elaborated of lever transference by the right forepaw in a definite zone--prior to and after the electrolytic damage of the left ventrolateral thalamic nucleus. It was found that even a slight damage led to disturbance of precise movements mostly expressed in the first two weeks; after that gradual normalization of the motor reactions took place. At morphological study of various pyramidal neurones and also satellite and general glia in the zone of presentation of the ventrolateral nucleus in the cerebral cortex a hypertrophy was discovered of the pyramidal cells and their processes in III and V layers, accompanied by active reaction of various glia forms. Morphometric processing and statistic analysis of the obtained data showed the dominance of structural compensatory changes observed in the cortex on the side of VL damage.     

Development of the hypothalamic-cortical interrelations in the ontogeny of the cat

Under chloralose narcosis, employing the evoked potentials method, studies have been made on the projection of the posterior hypothalamus to the frontal cortex in 1-30 days old kittens. The animals were divided into 3 age groups: 1-9, 10-19 and 20-30 days. Studies of the EPs in different points of pericruciate zone showed that these potentials are observed in all the investigated points from the first days of postnatal life. The latent period of responses in the youngest animals varied from 40 to 80 ms, exhibiting insignificant fluctuations depending on the cortical zone investigated. From the very beginning of postnatal life, in the same cortical zone the EPs may be observed in response to stimulation of the ischiadic nerve as well. In older animals, the latent period of the EPs decreases in all the points, the decrease being most significant near the crucial fissure. To the 30th day of postnatal life, the EPs in this zone with respect to their latency and configuration became quite similar to those in adult animals. In the third age period, the latency varies from 6 to 10 ms in the focus of maximum activity; with the removal of the recording electrode from this zone the latent period of the hypothalamo-cortical responses increases up to 30-40 ms. Overlapping of the EPs in response to central and peripheral stimulation was observed at all age periods.     

Specialization of cerebral hemispheres in the perception of Russian intonations

Relations between the brain hemispheres were studied during the human perception of various types of Russian intonations. Fifty healthy subjects with normal hearing took part in the tests based on the method of monaural presentation of stimuli—the sentences that represented the main kinds of Russian emotional and linguistic intonations. The linguistic intonations expressed: various communicative types of sentences; completeness/incompleteness of a statement; various types of the syntagmatic segmentation of the statements; various logical stress. Sentences that required the identification of the emotion quality were used to study the perception of emotional intonations. The results of statistical analysis of latent periods and errors made by the test subjects demonstrated a significant preference of theright hemisphere in perceiving emotional intonations and complete/incomplete sentences; sentences with different logical stress were perceived mainly by theleft hemisphere. No significant differences were found in the perception of various communicative types of sentences and statements with different syntagmatic segmentation. The obtained data also testify to a difference in the degree of the involvement of human hemispheres in the perception and analysis of prosodic characteristics of the speech in males and females.     

Protein metabolism in the cerebral hemispheres during the emotional-algesic stress

Emotional-algesic stress causes essential changes in the protein metabolism of cerebral hemispheres. These changes may be of great importance for the functioning of the brain and cause the disturbances of the higher nervous activity when the organism is influenced by the emotional stress factors.