[Responses of bulbo-spinal neurons during the expiration reflex in cats].

Activity of 129 bulbo-spinal neurons was studied during the expiration reflex elicited by mechanical stimulation of the vocal cords or by electrical stimulation of the superior laryngeal nerve in cats under nembutal anesthesia. It was found that besides expiratory and inspiratory neurons a great number of nonrespiratory bulbo-spinal units were activated. They were localized mainly within gigantocellular tegmental fields.

[Vestibular efferent neurons of the guinea pig forming projections into the saccule].

The distribution of vestibular efferent neurons projecting to the saccule and efferent neurons transmitting axons to the acoustic nerve (cochlear efferent neurons) has been studied in guinea pig by comparison using the method of retrograde axonal transport of horseradish peroxidase. The saccular efferent neurons are revealed bilaterally in the subendymal granular fundus of the fourth ventricle of the brain and more laterally of the facial nerve genu, ipsilaterally in the small-celled reticular nucleus as well as in nuclei of the supraolivary complex: nucleus of lateral oliva and lateral nucleus of the trapezoid body. The cochlear efferent neurons are localized ipsilaterally in the reticular caudal nucleus of the bridge in the anteroventral cochlear nucleus and in nuclei of lateral and medial olivae.

[A study of the otolithic membranes of the saccule and utricle of the guinea pig].

By scanning electron microscopy the otolith membranes of the sacculus and utriculus of adult guinea-pigs were examined. The spatial arrangement of otoconia was found to differ from the standard scheme. New forms of imperfect otoconia were detected.

[Possibilities of laser-endoscopic spectrum analysis in laryngology].

This paper discusses the potential application of a laser-endoscopic spectral analyzer in fibrolaryngoscopy for early detection of neoplasms (luminescence combined with spectrophotometry) as well as for examination of the laryngeal mucosa by measuring oxygenation and blood flow in microcirculation with the aid of spectrophotometry. The results of examinations of 35 patients have shown that the laser-endoscopic spectral analyzer can be used to perform premorphological rapid tests in cancer diagnosis and to assess the efficacy of therapeutic methods.

[Influence of the efferent vestibular system on the vestibulo-spinal reflexes in the guinea pig].

Influence of the efferent vestibular system on the vestibulo-spinal activity was investigated in the decerebrated, decerebellated guinea pigs. The efferent vestibular system was excited by electrical stimulation of the domain of efferent neurons in the medulla. Electromyographic activity of left and right triceps brachii was used as a test reaction.

[Impulse activity of slowly adapting pulmonary receptors during respiration].

Impulse activity of 50 pulmonary slow-adapting receptors (SAR) has been investigated in anesthetized cats during eupnea under conditions of quasi-static and dynamic lung inflation. During inspiration 74% SARs were found to have nonlinear relationship between the receptor frequency (F) and pulmonary volume (V), in 16% receptors the F-V relationship was linear. Impulse activity of 10% SARs had different characteristics.

[Brain stem neurons of the guinea pig that form projections into the ampullae of the anterior, lateral and posterior semicircular canals].

Brain stem neurons projecting to the ampullae of anterior, lateral and posterior semicircular canals (vestibular efferent neurons) were identified in guinea pigs using, retrograde labelling with horseradish peroxidase. Two groups of such neurons located bilaterally dorsal and ventral to the facial nerve trajectory were classified. A dorsal group contained vestibular efferent neurons to all three canals; these units were located at all the levels of the subependymal granular layer of the floor of the 4th ventricle lateral to the facial nerve genu and abducens nerve nucleus.

[Study of vestibular efferent neurons of the guinea pig by the technic of retrograde axonal transport of horseradish peroxidase and with fluorochromes].

Vestibular efferent neurons were identified in different structures of guinea pig medulla using retrograde labelling by horseradish peroxidase and transport-specific fluorochromes. Two groups of vestibular efferent neurons with bilateral projections were found. These groups were situated dorsally and ventrally to the facial nerve fibre pathway.

[Functional differentiation of afferents of the superior laryngeal nerve in the cat].

Excitability of the electrically stimulated superior laryngeal nerve afferents and reflex discharges in the respiratory motor nerves were studied on cats under light nembutal anesthesia. Three types of group A afferent fibres were differentiated according to their functional role in reflex response initiation. Low-threshold afferent fibres (A beta) are concerned with proprioceptive activation of laryngeal muscles, the group of A gamma afferents participates in regulation of the respiratory phase-switching mechanisms and high-threshold afferent fibres (A delta) support protective respiratory reflexes.

[Modulation of reflex discharges in the respiratory nerves of the cat upon stimulation of superior laryngeal afferents].

Cyclic changes of reflex discharges in phrenic, external and internal intercostal and lumbar nerves evoked by electrical stimulation of the superior laryngeal nerve were investigated in cats under light nembutal anaesthesia. Intensity of discharges and their latency varied in different nerves during the respiratory cycle. Reflex discharges of the greatest intensity with the shortest latency appeared at the end of the inspiratory or at the beginning of the expiratory phase in lumbar and internal intercostal nerves.