Brainstem and Cranial Nerves: Longitudinal Pathways of the Brainstem

2021 ◽  
pp. 99-104
Author(s):  
Kelly D. Flemming
Keyword(s):  
Spinal Cord ◽  
Eye Movements ◽  
Blood Vessels ◽  
Reticular Formation ◽  
Cranial Nerves ◽  
Ventrolateral Medulla ◽  
Unilateral Lesion ◽  
Horner Syndrome ◽  
Single Level ◽  
Autonomic Pathways

This chapter reviews pathways that are not at a single level of the brainstem but rather involve multiple areas with supratentorial input. The chapter highlights autonomic pathways, the reticular formation and chemically defined groups, and coordination of eye movements. Sympathetic fibers travel from the hypothalamus to the intermediolateral column in the spinal cord through the lateral brainstem. Patients with a unilateral lesion of the lateral brainstem may have ipsilateral Horner syndrome. The ventrolateral medulla, also a sympathetic region of the brainstem, projects to the spinal cord and is involved in the innervation of blood vessels in the limbs.

Gigantocellular vasodepressor area is tonically active and distinct from caudal ventrolateral vasodepressor area

1997 ◽  
Vol 272 (3) ◽  
pp. R731-R742 ◽  
Author(s):  
S. A. Aicher ◽  
D. J. Reis
Keyword(s):  
Spinal Cord ◽  
Reticular Formation ◽  
Kynurenic Acid ◽  
Sympathetic Nerve Activity ◽  
Raphe Nuclei ◽  
Ventrolateral Medulla ◽  
Medullary Reticular Formation ◽  
Nerve Activity ◽  
System 2 ◽  
Raphé Nuclei

The gigantocellular depressor area (GiDA) is a functionally defined subdivision of the medullary gigantocellular reticular formation where vasodepressor responses are evoked by glutamate microinjections (Aicher, S. A., D. J. Reis, D. A. Ruggiero, and T. A. Milner. Neuroscience 60: 761-779, 1994). The present experiments sought to determine whether the GiDA 1) tonically inhibits the sympathetic nervous system; 2) is necessary for baroreflex function; and 3) is functionally distinct from adjacent vasodepressor regions in the medullary reticular formation, including the midline raphe nuclei and the caudal ventrolateral medulla (CVL). Excitotoxic lesions of the GiDA abolished the baroreflex and significantly increased sympathetic nerve activity in anesthetized rats. Equivalent injections into the midline raphe nuclei elevated sympathetic activity but did not alter baroreflex responses. Therefore, the GiDA is functionally distinct from the raphe nuclei, although both contain tonically active sympathoinhibitory neurons. Because the effects of GiDA lesions were identical to those seen after lesions of the CVL, further studies were required to demonstrate that the GiDA and CVL are functionally and anatomically distinct. First, intramedullary injections of kynurenic acid produced hypertension and blocked the baroreflex when placed in the CVL, but not when placed in the GiDA. Second, muscimol inactivation of the RVL blocked the hypertension produced by excitotoxic lesions of the CVL, but failed to block the hypertension produced by similar lesions of the GiDA. Third, CVL neurons project to the RVL but not the spinal cord, whereas GiDA neurons project to the spinal cord but not the RVL. These studies show that the CVL and GiDA are both tonically sympathoinhibitory regions, but they are distinct with regard to their functional connectivity with other autonomic regions.

Eye Movements of the Dogfish Squalus Acanthias L

1965 ◽  
Vol 43 (1) ◽  
pp. 107-130
Author(s):  
A. JOHN HARRIS
Keyword(s):  
Spinal Cord ◽  
Eye Movements ◽  
Squalus Acanthias ◽  
Free Swimming ◽  
Spontaneous Movements ◽  
Excitatory State ◽  
Blind Area ◽  
Full Compensation ◽  
Central Excitatory State ◽  
Partial Compensation

1. A method for recording the positions of the eyes of a free-swimming dogfish is described. 2. The eyes of the dogfish do not compensate completely for the lateral swinging of the head which occurs during swimming. The labyrinthine apparatus and the extraocular musculature are capable of providing complete compensation, but this compensation is opposed by influences from the spinal cord. 3. Full compensation during swimming would stabilize only objects at infinity. Partial compensation serves to stabilize a plane of reference close to the fish. 4. Eye movements, allied with the normal zig-zag progression of the fish, serve to eliminate the blind area behind the fish. 5. Other movements of the dogfish's eyes are discussed, and arranged in five categories. 6. Spontaneous movements of the eyes of resting dogfish are described, and related to the eye movements of swimming dogfish. The spontaneous movements are suggested to be manifestations of an otherwise subliminal central excitatory state affecting turning and swimming.

Facial Ganglia - Anatomy, Symptomatology of Lesions and Biological Relevance

2021 ◽  
Vol 53 ◽  
pp. 41-50
Author(s):  
Ilya Lebedev ◽  
Alexander Bragin ◽  
Yulia Boldyreva ◽  
Artem Borsukov ◽  
Alexander Tersenov ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Facial Pain ◽  
Multidisciplinary Approach ◽  
Human Life ◽  
Cranial Nerves ◽  
Living Organism ◽  
Sympathetic Ganglia ◽  
Historical Background ◽  
Brain And Spinal Cord ◽  
The Brain

The article summarizes information about the head ganglia (the sympathetic ganglia and in the sensory cranial nerves). Gives а brief historical background on the history issue and relevance of the topic. Characterized by each node with its topography and lesion clinic. The described process of treatment, and prospects for new therapies. Raised the issue of the significance of the defeat ganglia, namely, the suffering of the sick and forced treatment costs (due to the complex differential diagnosis). In a biological sense, pain first appears in chordates and during evolution, as well as transformations of the brain and spinal cord, it acquires new types, localization and significance for the performance of a living organism. And facial pain, being a nosology with a multidisciplinary approach in diagnosis and treatment, demonstrates both its complexity and importance in human life.

Motoneuron properties during motor inhibition produced by microinjection of carbachol into the pontine reticular formation of the decerebrate cat

1987 ◽  
Vol 57 (4) ◽  
pp. 1118-1129 ◽  
Author(s):  
F. R. Morales ◽  
J. K. Engelhardt ◽  
P. J. Soja ◽  
A. E. Pereda ◽  
M. H. Chase
Keyword(s):  
Spinal Cord ◽  
Motor Activity ◽  
Reticular Formation ◽  
Input Resistance ◽  
Ventral Root ◽  
Monosynaptic Reflex ◽  
Pontine Reticular Formation ◽  
Active Sleep ◽  
Decerebrate Cat ◽  
Inhibitory Postsynaptic Potentials

It is well established that cholinergic agonists, when injected into the pontine reticular formation in cats, produce a generalized suppression of motor activity (1, 3, 6, 14, 18, 27, 33, 50). The responsible neuronal mechanisms were explored by measuring ventral root activity, the amplitude of the Ia-monosynaptic reflex, and the basic electrophysiological properties of hindlimb motoneurons before and after carbachol was microinjected into the pontine reticular formation of decerebrate cats. Intrapontine microinjections of carbachol (0.25-1.0 microliter, 16 mg/ml) resulted in the tonic suppression of ventral root activity and a decrease in the amplitude of the Ia-monosynaptic reflex. An analysis of intracellular records from lumbar motoneurons during the suppression of motor activity induced by carbachol revealed a considerable decrease in input resistance and membrane time constant as well as a reduction in motoneuron excitability, as evidenced by a nearly twofold increase in rheobase. Discrete inhibitory postsynaptic potentials were also observed following carbachol administration. The changes in motoneuron properties (rheobase, input resistance, and membrane time constant), as well as the development of discrete inhibitory postsynaptic potentials, indicate that spinal cord motoneurons were postsynaptically inhibited following the pontine administration of carbachol. In addition, the inhibitory processes that arose after carbachol administration in the decerebrate cat were remarkably similar to those that are present during active sleep in the chronic cat. These findings suggest that the microinjection of carbachol into the pontine reticular formation activates the same brain stem-spinal cord system that is responsible for the postsynaptic inhibition of alpha-motoneurons that occurs during active sleep.

Sign in / Sign up

Export Citation Format

Share Document