[Septal nuclei in the regulation of vago-sensitive neurons activity of the solitary nucleus in cats].

The descending influences of the septal nuclei (lateral nucleus--LSN and bed nucleus stria terminalis--BNST) on activity of viscero-sensory neurons of the nucleus of tractus solitarius (NTS) identified by stimulation of cervical part of the n. vagus were investigated in the cat anaesthetised by chloraloze-nembutal combination. It was found that out of 70 units recorded in the NTS area 50 were identified as those of primary and secondary input vagal neurons.

[The neuronal organization of the limbic (cingulo-)-visceral reflex arc].

The paper summarizes new electrophysiological data concerning the structural-functional organization of the limbic cortex and role of the rostral limbic region of visceral functions. Here are presented the results of a series of electrophysiological investigation of the focus of localization in the supracallosal (area 24) and infracallosal (area 25) part of the anterior cingulate gyrus of evoked potentials of maximal amplitude and minimal latent period to stimulation of pelvic, splanchnic and sciatic nerves. It was shown that evoked potentials of maximal amplitude and minimal latent periods to stimulation of viscero-somatic nerves are recorded in the supragenual area 24 in comparison with the infragenual area 25 of the anterior limbic cortex.

[Neuron mechanisms of the regulation of bulbar vagosolitary activity by structures of basolateral amygdala nuclei in cats].

Neuronal reactivity to single stimuli applied to both the peripheral nerves and the cortex, was the same in the cat solitary tract nucleus. The 1-20 Hz stimulation frequency rendered the reactivity either tonic in character or with reduced firing rate. A high degree of convergence (80.

[The neuronal organization of the amygdala-visceral reflex arch].

The paper summarizes the histomorphic, histochemical, autoradiographic, immune-histochemical and electrophysiological data on the structural-functional organization of the amygdalar complexes. While discussing the problem of neuron organization of the afferent and efferent groups in the amygdala-visceral arch the authors present their data of microelectrophysiological studies of the specific amygdala neuron reactions in response to stimulation of the vagus, ventric, and sciatic nerves, and of the second somatic sensor cortex zone. It was observed that interoceptive impulsation reaching the polysensor neurons of the central, corticomedial, and basolateral groups of the amygdala complex nuclei have no significant qualitative differences.

[Microelectrophysiologic analysis of the representation of the vagal, splanchnic, sciatic nerves and sensomotor region of the cortex in the central nucleus of the amygdala].

In anesthetized cats, a high degree of reactivity (82.2%) of neurons was found to visceral nerves and visceral stimulation (single shocks and 2, 5, 10, 20 Hz) in the central nucleus of amygdala. The majority of the neurons revealed tonic changes of spontaneous activity.

[Unit responses of the amygdaloid corticomedial nuclei to stimulation of the vagal, splanchnic and sciatic nerves].

Bipolar recording revealed EPs of maximal amplitude in stimulation of vagus, splanchnic and sciatic nerves in the region of amygdaloid corticomedial nuclei in anesthetized cats. A high degree of reactivity (68.3%) of neurons was found in this region to single-shock stimulation of the peripheral nerves.

[Neuronal reactions of the ventromedial hypothalamus to stimulation of gastric mechanoreceptors and to the intra-arterial administration of glucose and sodium chloride].

In anesthetized and immobilized cats, intact and with cut splanchnic nerves ("vagal" animals) of vagal nerves ("splanchnic" animals), high degree of responsiveness of hypothalamic neurons, with prevailing excitatory reactions, was found. The responses were obtained mainly to stimulation of gastric adapting mechanoreceptors. Information from the latters reaches the hypothalamic neurons through splanchnic and vagal afferents.

[Responses of different hypothalamic structures to stimulation of the viscero-caudal region of the nucleus of a the solitary tract of the medulla oblongata].

Responses of single units of anterior, ventromedial, lateral and posterior hypothalamus to stimulation of the caudal viscero-receptive region of nucleus tractus solitarius were recorded in anesthetized and immobilized cats. The patterns of the responses were mainly excitatory in all structures under study. The highest degree of reactivity was found for units in the lateral and posterior hypothalamus.

[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.

[Response of hypothalamic neurons to different groups of afferent fibers of the subdiaphragmatic vagus nerve].

Responses of single units of posterior, anterior, ventromedial and lateral hypothalamus to stimulation of abdominal trunk of the vagus nerve were recorded in anesthetized cats simultaneously with the action potentials of the cervical region of the vagus nerve. 28.1% of the neurons responded to the stimulation, the pattern of responses being mainly excitatory.

[Convergence of visceral afferent impulsation on hypothalamic neurons following stimulation of the vagus and splanchnic nerves].

Responses of single hypothalamic units to stimulation of the vagal, splanchnic and sciatic nerves and to photic stimulation were studied in anaesthetized, curarized cats. Most of the reactive neurons of the posterior and anterior hypothalamus responded to stimulation of vagus and splanchnicus. The pattern of responses of these polysensory units reactive in most cases to sciatic nerve and (or) photic stimulation too, were mainly unidirectional, nonreciprocal and excitatory in case of stimulation of visceral afferents of parasympathetic and sympathetic nerves.

[Response of neurons of the anterior and posterior regions of the hypothalamus to stimulation of the vagus and sciatic nerves and photic stimulation].

Evoked activity of single units in anterior and posterior hypothalamus to vagal, sciatic nerves, and photic stimulation was studied in anesthetized and immobilized cats. The responsiveness of neurons of the posterior hypothalamus was 66, 77 and 37% to vagal, sciatic nerves and photic stimulation, respectively, and of the anterior hypothalamus -- 47, 62 and 48%. Vagal stimulation was found to be the more effective for units of the posterior hypothalamus.

[Background and evoked activity of hypothalamic neurons during development in cats].

In acute experiments on anaesthetized kittens, studies have been made on the background and the evoked activity of hypothalamic neurons elicited by sensory stimuli. It was shown that already from the 2nd day of postnatal life, it is possible to observe the background impulse activity of the neurons in the posterior hypothalamus. The evoked reactions to stimulation of the sciatic nerve were recorded at the 4-5th day of postnatal life.