Dorsolateral Pons Research Articles

Role of the periaqueductal grey in vocal expression of emotion

In 32 squirrel monkeys (Saimiri sciureus) the role of the periaqueductal grey has been investigated by combined stimulation/lesioning and by neuroanatomical experiments. The results are as follows. Firstly, periaqueductal lesions invading the laterally adjacent tegmentum abolish species-specific calls elicitable by electrical brain stimulation. This holds for stimulation sites rostral as well as caudal to this area. The only vocalizations which survive are phonations of an artificial character which can be evoked from the lateral medulla. Spontaneous vocalizations also seem to be abolished. Secondly, vocalizations elicited from the periaqueductal grey are not affected by bilateral lesions in vocalization-eliciting areas rostral to it, but are abolished by lesions in the dorsolateral pons and ventrolateral medulla. Thirdly, the periaqueductal grey receives direct projections from all vocalization-eliciting areas tested, viz. the precallosal cingulate gyrus, gyrus rectus, medial amygdata, central amygdaloid nucleus/substantia innominata, nucleus striae terminalis, dorsal hypothalamus, midline thalamus, periventricular grey, dorsolateral and ventrolateral midbrain tegmentum. Fourthly, the periaqueductal grey projects directly to the nucleus ambiguus, the site of the laryngeal motoneurones. The course of the main bulk of fibres corresponds to the lesion sites effective in abolishing periaqueductally elicited vocalizations. From these results, it was concluded that the caudal periaqueductal-lateral tegmental area is a necessary relay station for all external and internal stimuli capable of inducing species-specific calls. Its position within the stimulus-response loop seems to be on the output side, immediately above the level of motor-corrdination but below that of stimulus recognition.

Atonia after carbachol microinjections near the locus coeruleus in cats

The effect of microinjections of carbachol into the dorsolateral pontine tegmentum on the behaviour of cats is investigated. Injections of small amounts (50 and 500 ng) of carbachol into the pontine reticular formation induced muscular atonia in otherwise awake animals. The atonia is not due to cholinergic stimulation of the noradrenergic cells of the locus coerulus of the dorsolateral pons, since the most effective sites were situated ventrally to the locus coeruleus and alpha- and beta-adrenergic blocking agents did not affect the atonia. The results are discussed in view of the postulated role of the locus coeruleus in paradoxical sleep.

The nucleus corporis pontobulbaris of the North American opossum.

The nucleus of the pontobulbar body (PBu) in the North American opossum is located, for the most part, adjacent to the motor root of the trigeminal nerve. Material prepared by degeneration and autoradiographic methods shows that the PBu receives projections from the facial motor-sensory cortex, red nucleus, spinal cord and cerebellum. The latter fibers probably take origin within the fastigial nucleus. Each of the afferent connections ends in a restricuted part of the PBu, but there is considerable overlap. Use of the horseradish peroxidase technique reveals that the PBu projects to the spinal cerebellum (anterior lobe, pyramis and paramedian lobules), to visual-auditory areas of the vermis and to the lobus simplex as well as to crus I and II of the hemispheres. Although there is some topography to such projections, it is not sharply defined and many regions of the PBu contain labelled neurons after injections of horseradish peroxidase into widely separate areas of the cerebellar cortex. Because of its embryogenesis and position, the PBu is often considered part of the dorsolateral basilar pons. It appears from our material, however, that the organization of PBu afferent and efferent connections is different from that of the adjacent basilar pons, and arguments for considering the PBu a separate precerebellar nucleus are presented.

Changes in the Breuer-Hering reflexes following rostral pontine lesion

The lung stretch reflex characteristics of unanesthetized decerebrate cats were determined using servo-controlled lung volume changes before and after bilateral lesion of the dorsolateral rostral pons in the region of nucleus parabrachialis medialis (NPBM). During the inspiratory phase the time-dependent threshold curve for inspiratory inhibition by lung inflation was shifted to larger volumes after lesion with no change in the constant describing its rate of decay. During the expiratory phase the gain of the inflation reflex was found to be increased by lesion, but otherwise to remain qualitatively the same. Deflations during the expiratory phase revealed a prolonged central inhibitory state with reduced rate of decay late in expiration. It is concluded that with intact vagi structures in the region of NPBM constitute but one of at least three sources of inspiratory inhibition, feedback derived from peripheral lung stretch receptors and from caudal pontine or medullary neurons also being involved. It is also concluded that the structures in the vicinity of NPBM affect the switching mechanisms differently during the two phases of the cycle: During inspiration they contribute a tonic threshold lowering input to the inspiratory 'offswitch'; whereas, during expiration they provide inspiratory-facilitatory influences late in the phase.

Mechanisms of renal release of renin by electrical stimulation of the brainstem in the cat.

Electrical stimulation of the dorsolateral pons for 5-minute periods in anesthetized cats produced a rise in blood pressure of 40%, a reduction in renal blood flow of 28%, and an increase in the rate of renin release (the product of renal plasma flow and the venoarterial difference of plasma renin activity) of more than 100% in intact kidneys. Comparison of an intact kidney with the contralateral denervated one showed that denervation abolished the decrease in renal blood flow and the increase in renin release induced by pontine stimulation. Infusion of phenoxybenzamine into an otherwise intact kidney prevented the decrease in renal blood flow on that side, but brain-induced renin release was at least equal to that from the contralateral kidney in which the vasomotor response remained unchanged. Treatment of the animal with intravenously administered propranolol (1.3-3.0 mg/kg) abolished any rise in renin release, although propranolol accentuated the reduction in renal blood flow during stimulation of the brainstem. We concluded that the increased renal release of renin induced by electrical stimulation of a pressor area of the brainstem was dependent on intact renal nerves and on mechanisms blocked by propranolol but was not dependent on changes in renal blood flow or on renal alpha receptors.

Relationships between medullary depressor region and central vasopressor pathways.

ARTICLESRelationships between medullary depressor region and central vasopressor pathwaysDW Snyder, and GL GebberDW Snyder, and GL GebberPublished Online:01 Nov 1973https://doi.org/10.1152/ajplegacy.1973.225.5.1129MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByPhysiology and Pathophysiology of Arterial Flow2 February 2015Cardiovascular Physiology4 November 2013Medical Images and Physiological Signals4 November 2013Physiology of Ventilation4 November 2013Anatomy of the Cardiovascular Apparatus4 November 2013Arterial Flow3 March 2014Anatomy of the Ventilatory Apparatus4 November 2013Physiology and Pathophysiology of Arterial Flow3 June 2014Paramedian reticular nucleus: a thermolytic area in the rat medulla oblongataPfl�gers Archiv European Journal of Physiology, Vol. 417, No. 4Cardiovascular and muscle tone changes produced by microinjection of cholinergic and glutamatergic agonists in dorsolateral pons and medial medullaBrain Research, Vol. 514, No. 1Existence of a powerful inhibitory mechanism in the medial region of caudal medulla—with special reference to the paramedian reticular nucleusBrain Research Bulletin, Vol. 20, No. 4PARADOXICAL CARDIOVASCULAR RESPONSE TO VISCERAL AFFERENT STIMULATION IN THE ESTABLISHED SPONTANEOUSLY HYPERTENSIVE RATClinical and Experimental Pharmacology and Physiology, Vol. 12, No. 1Evidence for two distinct sympathoinhibitory bulbo-spinal systemsNeuropharmacology, Vol. 23, No. 1Interaction of Cardiovascular Reflexes in Circulatory Control1 January 2011Cholinergic mechanisms in the nucleus tractus solitarii and cardiovascular regulation in the ratEuropean Journal of Pharmacology, Vol. 88, No. 1FUNCTIONAL ORGANIZATION OF CENTRAL CARDIOVASCULAR PATHWAYSClinical and Experimental Pharmacology and Physiology, Vol. 8, No. 3Neural organisation and control of the baroreceptor reflex21 June 2005Neuronal Regulation of Blood PressureTonic descending inhibition of the spinal somato-sympathetic reflex from the lower brain stemJournal of the Autonomic Nervous System, Vol. 2, No. 2Bulbospinal Control of Sympathetic Nerve DischargeSpinal pathways mediating splanchnic sympathetic excitation and sympathetic silent periods in the ratBrain Research, Vol. 167, No. 2Raphe Inhibition of Sympathetic Preganglionic NeuronsScience, Vol. 203, No. 4376Influence of a cholinergic agent, oxotremorine, on sympathetic reflexesEuropean Journal of Pharmacology, Vol. 52, No. 3-4Effect of hypothalamic stimulation in spontaneously hypertensive and Wistar-Kyoto ratsEuropean Journal of Pharmacology, Vol. 51, No. 4Neuronal Mechanisms Influencing Transmission in the Baroreceptor Reflex ArcDifferential effect of baroreceptor reflexes and clonidine on frequency components of sympathetic dischargeEuropean Journal of Pharmacology, Vol. 36, No. 1Inhibition of centrally-evoked pressor responses by diazepam: Evidence for an exclusively supramedullary actionNeuropharmacology, Vol. 14, No. 9Bulbo-spinal neurons activated by baroreceptor afferents and their possible role in inhibition of preganglionic sympathetic neuronsPfl�gers Archiv European Journal of Physiology, Vol. 356, No. 2Some properties of sympathetic neuron inhibition by depressor area and intraspinal stimulationPfl�gers Archiv European Journal of Physiology, Vol. 357, No. 3-4Central neural regulation of heart and blood vessels in mammalsProgress in Neurobiology, Vol. 5 More from this issue > Volume 225Issue 5November 1973Pages 1129-1137 Copyright & PermissionsCopyright © 1973 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1973.225.5.1129PubMed4745211History Published online 1 November 1973 Published in print 1 November 1973 Metrics

Four aspects of trigeminal nucleus and a paradox.

Four aspects of trigeminal nucleus and a paradox.

Intrinsic periodicity of the pontile pneumotaxic mechanism.

Microelectrode explorations in the region of the pneumotaxic center (dorsolateral rostral pons) have revealed the presence of numerous neurons discharging synchronously with respiration. To determine whether these discharges are intrinsic in origin or are activated by impulses from other regions, half of the pons was isolated by means of sectioning procedures, and the isolated region was explored for periodic discharges with microelectrodes. In preparations where hemisections were made but connections across the mid-line were left intact, discharges synchronous with respiration were found. In addition, two types of periodic discharge not synchronous with respiration were found; however, there is no conclusive evidence which relates these discharges to respiration. In the completely isolated hemi-pons (hemisection plus sagittal section), no definitely periodic discharges were found. It is therefore concluded that the periodic respiratory discharges in the pneumotaxic center are probably not intrinsic in origin, but are dependent on connections with other regions of the brain stem.

HYPOTHALAMIC REGULATION OF SLEEP IN RATS. AN EXPERIMENTAL STUDY

The essential role of the nervous system in the regulation of the sleep-waking rhythm of higher animals is now widely recognized. No less a person than von Economo, however, drew attention to the fact that the phenomenon of sleep cannot be accounted for by a mere functional change of the central nervous system from its condition during the waking state. It is indeed an important fact that the function of sleep, instead of being characteristic of higher animals, is also observed in organisms which do not possess a central nervous system, and even in several vegetable species. It is therefore impossible to attribute this mysterious function to any special organ. Since all experimental work on sleep has hitherto been confined to mammals, chiefly to cats and monkeys, practically no data concerning the comparative physiology of this phenomenon are available. Nevertheless, it seems probable that during the phylogenetic development the function of sleep, together with many other mechanisms, was progressively centralized into the nervous system from which organ all changes, characteristic of sleep, were ultimately effected. This centralization proceeded so far that the alternation of wake and sleep seems to be governed in mammals by a circumscribed area of the central nervous system, capable of determining physical and psychical activities. The existence of this “centre” for the regulation of sleep is generally accepted by students of this subject.

TONIC AND REFLEX FUNCTIONS OF MEDULLARY SYMPATHETIC CARDIOVASCULAR CENTERS

TONIC AND REFLEX FUNCTIONS OF MEDULLARY SYMPATHETIC CARDIOVASCULAR CENTERS