Topical organization of the projections of neurons of the substantia nigra and the ventral field of the tegmentum of the midbrain to the head of the caudate nucleus of the cat

Neuroscience and Behavioral Physiology -     

Asymmetry of the internal connections of the striate cortex of the cat in the projection zone of the center of the field of vision

Studies were carried out on the organization of the internal connections of the striate cortex in cats in the projection zone of the center (0–5°) of the field of vision by microintophoretic application of horseradish peroxidase to electrophysiologically identified orientational columns. The area containing neurons showing retrograde labeling in most cases extended in the mediolateral direction. Labeled cells were located in the upper (II, III) and lower (V, VI) layers of the cortex, and the shapes and orientations of the areas containing labeled neurons in these layers coincided. Spatial asymmetry was detected in the distribution of labeled neurons relative to the orientational column studied. Labeled cells were located predominantly medial to the columns, regardless of the distance from the projection of the area centralis. Considering the visuotopical map of field 17, the asymmetry detected here provides evidence that neurons in orientational columns have more extensive connections with neurons of the peripheral part of the cortex. An asymmetrical distribution of “silent” zones around the receptive fields of neurons in orientational columns is suggested, and that these appear to receive influences from the periphery of the visual field. Laboratory of Visual Physiology and Laboratory of Central Nervous System Morphology, I. P. Pavlov Institute of Physiology, Russian Academy of Sciences, 6 Makarov Bank, 199034 St. Petersburg, Russia. Translated from Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 82, No. 12, pp. 23–29, December, 1996.     

Effects of the lesion of the postcommissural part of the septum on the behavior of the rat.

The effects of the lesion of the postcommissural part of the septum on behavior of the rat has been studied. Results may be summarized as follows. An increase in the exploratory behavior in the open field which decreases rapidly; a decrease in the number of defecations in this test and a decrease in time leaving a dark environment for exploration. In the shuttle box test, no facilitation of the acquisition, but a permanent and quite significant increase in the intertrial activity has been found. We conclude that the lesions tend to decrease the emotivity of the subjects. An interpretation on the basis of the species -- specific defensive reactions explains the transitory and permanent effects of the lesions on the spontaneous activity.     

Characteristics of the topographic interrelation of the head of the pancreas and the duodenum and pathology of the organs of the pancreatoduodenal area

Seventy pancreatoduodenal complexes of 55 patients with chronic pancreatitis and tumours of this zone and 15 patients died from other diseases are studies histotopographically . The pieces of the pancreatic head tissue in the medial wall of the duodenum were found in 12 cases of the first group and in 4 control cases. The pancreatic tissue consisted either of all elements of this organ or cystically dilated ducts and seemed to infiltrate different layers of the duodenum wall. Three variants of the pancreatic head structure are suggested on the basis of anatomo-topographical interrelationships of the pancreatic head and duodenum. In 12 out of 14 cases chronic pancreatitis and carcinoma of organs of this zone were combined with the variants of the pancreatic head structure, in 2 cases there was a true heterotopy . Pathogenetic significance of these variants for the development of chronic pancreatitis is discussed.     

Influence of the level of the transmembrane potential on the dynamics of the extinction of the amplitude of the synaptic reactions of the snail under voltage clamping conditions

The influence of the level of the transmembrane potential on the dynamics of the extinction of the amplitudes of summary excitatory postsynaptic currents arising in identified giant parietal neurons in response to rhythmic stimulation of the intestinal nerve was investigated in a preparation of the isolated CNS of the common snail in order to identify the possibility of the participation of the postsynaptic element in synaptic plasticity. It was demonstrated that, at a greater value of the transmembrane potential, the decrease in the amplitudes of the postsynaptic currents which have been induced by rhythmic stimulation takes place more rapidly. It was also demonstrated that at a higher frequency of stimulation of the nerve, the effect of the influence of the membrane potential level on the dynamics of the synaptic reactions is more prominent. The data obtained may be regarded as an argument in favor of the possibility of the participation of the post-synapse in plasticity. This study was partially supported by the Russian Basic Research Fund (project No. 94-04-12209). Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow. Translated from Zhurnal Vysshei Nervnoi Deyatel'nosti imeni I. P. Pavlova, Vol. 45, No. 1, pp. 171–179, January–February, 1995.     

Effect of the conditions of adaptation of the optic analyzer to the function of the thermoreceptors of the human skin

Summary A discussion is presented of the effect produced by light stimulation applied to the optic analyzer alone on the function of the temperature analyzer. The cutaneous-temperature analyzer was kept on constant illumination and temperature. The light effects from the retinal photoreceptors on the cutaneous thermoceptor system led to reflex changes of the functional rate of the latter. Conditions of the optic analyzer of light adaptation caused reflex adjustment of cold receptors as to heating. Dark adaptation of the eyes changed the functional state of the cold receptors, corresponding to their adjustment to low temperatures.(Presented by Active Member AMN SSSR V. V. Parin) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 57, No. 3, pp. 3–6, March, 1964     

Characteristics of the influences of the centrum medianum of the thalamus on the neuronal activity of the caudate nucleus

The specific character of the relationship of the baseline cellular activity of the caudate nucleus to the features of the impulse activity of the centrum medianum of the thalamus has been identified in chronic microelectrode experiments. Reciprocal changes in the bioelectrical activity were recorded in the first group of cells, with a low action potential repetition frequency, while unidirectional changes with reorganizations in the intralaminar nucleus were recorded in the second. The activation of the cells of the centrum medianum of the thalamus was accompanied during the formation of an instrumental conditioned defense reflex by the formation of a pattern of impulse activity in neurons of the neostriatum which coincided in sign with the reorganizations which were characteristic during the investigation of the baseline activity. It is hypothesized that the features of the internal structure of the caudate nucleus underlie such a relationship. Laboratory of Physiology of Higher Nervous Activity, I. P. Pavlov Institute of Physiology, Russian Academy of Sciences, Saint Petersburg. Translated from Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 80, No. 1, pp. 102–108, January, 1994.