Convergence of visceral and somatic afferents on single neurones in the reticular formation of the lower brain stem in dogs.

The reticular formation of the lower brain stem contains neuronal circuits for the generation of sympathetic tone, respiratory rhythm, muscle tone and the control of vigilance. In anesthetized dogs single neurone activities were recorded in the medial two-thirds of the reticular formation to investigate the organizing principles of this multifunctional system. The results from 110 recordings demonstrate that single neurones receive information from somatosensory afferents of skin, joints and muscles together with afferents from baro-, chemo- and lung inflation and deflation receptors.

Integrative neurovegetative and motor control: phenomena and theory.

The general problem of specificity and the existence of separate central control systems for different peripheral systems is handled and exemplified by the control of circulation, respiration and motor innervation. The considerations are based on several earlier experimental studies of spontaneous coordinations of rhythmic activities in anaesthetized dogs and conscious men and microelectrode recordings and local cooling experiments in the brain stem of anaesthetized dogs and cats. Analysis of findings and logical deductions result in the statement that central control systems must be partly identical and that the usual criteria of labelling central neurones according to their coordination to specific control systems are necessary but not sufficient.

Neurophysiological background of central neural cardiovascular-respiratory coordination: basic remarks and experimental approach.

This paper is comprised of a review of past contributions and their theoretical consequences and a presentation of new results in studies of the origin of sympathetic rhythms and tone. Two basic mechanisms are involved: a primary intracentral coupling with the main cardiovascular-respiratory rhythm (MCRR) generator and a secondary reflex coupling. It was found that the activity and rhythms of certain sympathetic efferents, such as the cervical sympathetic, are closely related to the MCRR.

Nucleus of the solitary tract and the J reflex.

Experiments were carried out on cats anaesthetized with chloralose-urethane with a view to defining certain central pathways for the J reflex elicited by the right atrial injection of phenyldiguanide. The resulting motor inhibition was manifested by reduction in the amplitude of the knee jerk. The dorsal surface of the medulla was exposed and free riding platinum quartz electrodes were introduced into the nucleus of solitary tract.