Projections of the central cerebellar nuclei to the intralaminar thalamic nuclei in cats

Projections of the central cerebellar nuclei to the intralaminar thalamic nuclei were studied in cats with the use of light and electron microscopy. Almost all intralaminar nuclei were shown to obtain cerebello-thalamic projections. The entire complex of the central cerebellar nuclei serves as a source of such projections; yet, involvement of different nuclei is dissimilar. Destruction of the central and, especially, caudal regions of the fastigial nucleus evoked in the intralaminar thalamic nuclei degenerative changes in the nerve fibers (from swelling and development of varicosities up to total fragmentation). Pathological phenomena could be noticed in the most caudal regions of the above thalamic nuclear group, including the medial dorsal nucleus. Projections of the cerebellar interpositus nucleus were directed toward nearly the same regions of the intralaminar nuclei; degeneration was more intensive (covered thecentrum medianum) when posterior regions of the interpositus nucleus were destroyed. Destruction of the lateral cerebellar nucleus evoked a similar pattern of pathological changes, but degeneration was also observed in some structures of the ventral and anterior nuclear groups of the thalamus. Electron microscopic examination showed that degeneration of dark and light types developed in the fiber preterminals and terminals. It can be concluded that the central cerebellar nuclei project not only to the ventral complex of the thalamic nuclei, but also to the anterior, medial, and intralaminar nuclear groups (rostral and caudal portions).     

On the statistical distribution of volumes of cell nuclei and on the dependence of volumes of cell nuclei and DNA amounts in the cell nuclei

Conclusion Based on the simplified model of the cell nucleus it has been shown that (V) is Gaussian. It follows also from this model the independence ofX andV. A number of further reasons for independence ofX andV is shown too.     

Functional interactions between the intralaminar nuclei of the thalamus and the caudate nuclei in the formation of motor programs

It has been shown that at the beginning of motor program forming, homogeneous and cyclic excitations take place between the nonspecific thalamic structures and caudate nuclei. Later on reciprocity of the afferent inflows to the nuclei under consideration occurs, that indicates a different pattern of the involvement of these structures into intercentral integration controlling avoidance behavior.     

On the anatomical organization of the vagal nuclei

The neurons of origin of the right vagus and its components in both the monkey (Macaca fascicularis) and albino rats were localized by the retrograde transport of horseradish peroxidase (HRP) applied to the stomach wall, the vagal trunk and its recurrent laryngeal branch. An attempt was also made to localize the neurons forming the superior laryngeal nerve and those supplying the thoracic organs by a combination of operative procedures. The results showed that the stomach was innervated by neurons distributed throughout the entire rostrocaudal extent of the dorsal motor nucleus (DMN) on both sides of the brain stem. Neurons scattered throughout the entire extent of the DMN and nucleus ambiguus (NA) supplied the thoracic viscera. There did not appear to be any topographic arrangement in the DMN neurons supplying the abdominal and thoracic viscera as reported by other workers, and there was no clear evidence of crossing of vagal fibers in the monkey brain stem, though such crossing was seen in the rat brain stem. Both the superior and inferior ganglia of the vagus nerve were labeled following application of HRP to the vagal trunk. Neurons in the caudal part of the NA gave rise to fibers in the ipsilateral recurrent laryngeal nerve, at least on the right side. The neurons giving rise to the superior laryngeal nerve could not be delineated in this study. In all the experimental procedures described, the hypoglossal nucleus was labeled only after applying HRP to the hypoglossal nerve.     

On the chemical constitution of cometary nuclei

The observed properties of comets and the experiments of Anderset al. suggest that during the condensation of the outer parts of the solar system from the solar nebula-assumed to contain most of the C in the form of CO, the remaining O mostly in the form of H₂O, and the excess H as H₂ molecules-besides the most stable hydrocarbon (CH₄) also considerable quantities of heavier hydrocarbon were formed. When the surface of the nucleus is warmed up in re-approaching the sun, part of the solar quanta having sufficient energy for dissociating such molecules, exothermic reactions, for instance such leading, to the observed C₂ and C₃ molecules may be expected; an inhomogeneous and porous structure of the nucleus would explain the observed occurrence of short-lived discrete jets, in which a small fraction of the CO could be ionized. Since also N must be present in some quantity (observed mainly was CN and N₂ ⁺), the formation of more complex organic molecules must also have taken place. To which extent complex interstellar molecules can have survived the formation of the solar system is hard to say on the basis of present knowledge of the origin of the solar system.     

The effect of stimulation of the amygdala basolateral nuclei on the neuron activity of Deiters vestibular nuclei in rabbits

A modulating character of the amygdala basolateral nuclei effect upon the vestibular sensory system was determined in rabbits [correction of rats]. A mechanism of the descending effect of the amygdaloid complex on the activity of the Deiters nucleus neurons, is discussed.