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Neurophysiological Perspectives
Published in Marlysa Sullivan, Laurie C. Hyland Robertson, Understanding Yoga Therapy, 2020
Marlysa Sullivan, Laurie C. Hyland Robertson
The neural platform of defensive immobilization is thought to be activated in response to extreme threat, danger, or terror. Engagement of this platform results in a dramatic slowing of the body’s processes to the minimum necessary for survival. Defensive immobilization diminishes heart rate, muscle tone, and all bodily systems to the lowest possible energy output. The branch of the vagus nerve originating in the brainstem’s dorsal motor nucleus is thought to be largely responsible for this response. This neural platform, referred to as the death-feigning response, is the most passive response to stressful situations. As a response to a perception of extreme threat, a combined physiological state of immobilization or shutdown is connected with emotional or behavioral states that might include disembodied or dissociative attributes.
Anatomy and Function of the Intrathoracic Neurons Regulating the Mammalian Heart
Published in Irving H. Zucker, Joseph P. Gilmore, Reflex Control of the Circulation, 2020
Parasympathetic Neurons. In dogs, cats, and nonhuman primates the somata of the efferent preganglionic parasympathetic neurons that regulate the heart are located primarily in the ventral lateral region of the nucleus ambiguus, few being located in the dorsal motor nucleus and the intermediate zone between these two nuclei (Armour and Hopkins, 1984; Hopkins and Armour, 1982, 1984). Although it has been reported that neurons in the dorsal motor nucleus are concerned primarily with decreasing cardiac inotropism while those in the nucleus ambiguus are concerned primarily with decreasing heart rate (Geis and Wurster, 1980), neurons in both of these medullary regions appear to be involved in, for instance, regulating cardiac inotropism (Hopkins and Armour, 1982). The efferent axons of these neurons synapse on the perikarya of efferent postganglionic parasympathetic neurons in the ganglionic plexi of the atria (Ardell and Randall, 1986; Blomquist et al., 1987) and ventricles (Priola, 1980), these efferent postganglionic parasympathetic neurons innervating cardiac tissue.
Ascending Projections of the Solitary Tract Nucleus
Published in I. Robin A. Barraco, Nucleus of the Solitary Tract, 2019
G. J. Ter Horst, C. Streefland
Although beyond the scope of this chapter, for completeness it is worth mentioning NTS projections in the medulla oblongata. Target areas in the medulla oblongata are the dorsal motor nucleus of the vagus,9,11,18 the nucleus ambiguus and retroambiguus area,9-12,14 the rostral and caudal ventrolateral reticular nuclei,9,10 the inferior olive,9,10 the lateral reticular formation,8-11 the spinal trigeminal nuclei,9-11 the hypoglossal,9-11,14 facial10 and motor trigeminal11,13,14 nuclei, and the supra-trigeminal region.13,14 Besides, Phaseolus vulgaris lectin tracing studies show intrasolitary tract nucleus projections11 that probably interconnect the subdivisions of the nucleus to enable integration of information relayed to various parts of the NTS by the different sensory systems.
Stereotaxic-assisted gene therapy in Alzheimer’s and Parkinson’s diseases: therapeutic potentials and clinical frontiers
Published in Expert Review of Neurotherapeutics, 2022
Samar O. El Ganainy, Tony Cijsouw, Mennatallah A. Ali, Susanne Schoch, Amira Sayed Hanafy
As deficits in dopaminergic neurons located in nigrostriatal pathway are the chief players in PD pathogenesis and associated motor and affective symptoms [89], PD can be considered a focal disorder. In addition, cholinergic, adrenergic, or serotonergic neuronal loss has been demonstrated in the nucleus basalis of Meynert, dorsal motor nucleus of the vagus nerve, pedunculopontine nucleus, raphe nuclei, hypothalamus, and olfactory bulb with variable extents [90]. Braak et al. have described an elegant, but not yet fully accepted, staging system. In stage 1–2, which are presymptomatic, Lewy bodies accumulate in the olfactory bulb/anterior olfactory nucleus and medulla oblongate/pontine tegmentum. Stage 3 involves the loss of melanized neurons and Lewy body spread in the substantia nigra. Finally in stage 4, the pathology reaches the temporal limbic cortex and includes the locus coeruleus and amygdala [91]. Given the focal nature of PD, it could represent a more plausible target for sterotaxically delivered therapeutics over AD. Although the hippocampus is the most affected brain region in AD and generally responsible for the amnesic manifestations, other brain areas, primarily the cortex, are highly involved in disease pathogenesis as well [61].
Spinal cord involvement in Lewy body-related α-synucleinopathies
Published in The Journal of Spinal Cord Medicine, 2020
Raffaele Nardone, Yvonne Höller, Francesco Brigo, Viviana Versace, Luca Sebastianelli, Cristina Florea, Kerstin Schwenker, Stefan Golaszewski, Leopold Saltuari, Eugen Trinka
The dorsal motor nucleus of the vagus innervates the striated muscles of the pharynx, larynx, and esophagus, while the preganglionic neurons of the dorsal motor nucleus of the vagus innervate the Auerbach’s plexus and in the Meissner’s plexus. The parasympathetic excitatory input arises from spinal roots S2-S4 and is transmitted to the anus, rectum, and descending colon. Preganglionic inhibitory sympathetic neurons arise from spinal roots T10-L2, reach the celiac and superior mesenteric ganglia, and innervate the small intestine, the ascending and transverse colon and, via the pelvic ganglion, the internal anal sphincter.75 However, reflex pathways mediating defecation and -bladder control differ markedly.76,77 Large intestine innervation relies on the Auerbach's plexus, which is also affected in PD, and a spinal reflex loop.75 Pathologic involvement of the afferent portion of this spinal reflex loop is likely to contribute to constipation and a sensory deficit may contribute to inhibition of the defecation reflex in the elderly.77
The Vagus Nerve and the Celiaco-mesenteric Ganglia Participate in the Feeding Responses Evoked by Non-sulfated Cholecystokinin-8 in Male Sprague Dawley Rats
Published in Endocrine Research, 2020
Amged I. Dafalla, Thaer R. Mhalhal, Kenneth Hiscocks, John Heath, Ayman I. Sayegh
The vagus nerve comprises the main parasympathetic innervation of the gastrointestinal tract, with cell bodies located in the nodose ganglia (the sensory/afferent portion) and the dorsal motor nucleus of the vagus (DMV, the motor/efferent portion).9,10 The splanchnic nerve comprises the main sympathetic innervation of the gut and also contains visceral afferent and efferent fibers. The cell bodies of the first-order neurons of this nerve reside in the pre – and paravertebral ganglia along the spinal cord, whereas the cell bodies of the second-order neurons reside in the celiaco-mesenteric ganglia, located between the celiac and the cranial mesenteric arteries.11,12 Although both nerves contain efferent and afferent fibers, the majority of these fibers are afferents e.g. over 85% of the fibers in the vagus nerve are afferents.9,10,13,14