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Developmental Diseases of the Nervous System
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
James H. Tonsgard, Nikolas Mata-Machado
Induction of the nervous system is regulated by genes controlling dorsal–ventral longitudinal organization and genes affecting the anterior–posterior axis, creating transverse divisions or segments. Patterning of the dorsal–ventral axis results in four longitudinal domains of the central nervous system (CNS). Patterning along the anterior–posterior axis results in segmentation of the CNS into the forebrain, midbrain, hindbrain, and spinal cord (Figure 9.3). The rostral end of the neural tube undergoes extensive changes, forming three dilations or segments: the prosencephalon or forebrain, the mesencephalon or midbrain, and the rhombencephalon or hindbrain. The prosencephalon divides transversely to form the telencephalon and diencephalon. Lateral division or cleavage of the telencephalon produces two paired structures, which become the cerebral hemispheres. The rhombencephalon eventually divides into the metencephalon, which becomes the pons and cerebellum, and the myelencephalon, which becomes the medulla (Figure 9.3).1
Chronic Fatigue Syndrome: Limbic Encephalopathy in a Dysregulated Neuroimmune Network
Published in Jay A. Goldstein, Chronic Fatigue Syndromes, 2020
Remembering that the limbic system amplifies and refines the control and function of the hypothalamus, just as the hypothalamus does for the brain stem, we can appreciate its role in PMS.78 The limbic system permits primitive cognitive functions and primary emotions. The heteromodal and paralimbic areas amplify and regulate the control of the limbic system in a more complex and sophisticated manner, so that state variables (cognition and attitude) have more of an influence. Temporolimbic structures do not have their primary effect in the reverberating circuit proposed by Papez. This concept proposes that the “limbic” cortex, which “rims around” the medical aspect of the telencephalon is a largely self-contained functional system.79 Rather, they directly innervate structures downstream in the neuraxis: the diencephalon, brain stem, and even the spinal cord. All of these structures have feedback or feedforward relationships with one another, but if the concept of limbic derangement of normal physiology were integrated into general medical thinking, many disorders (not just CFS, although CFS incorporates many of them) would be better understood.
Discussions (D)
Published in Terence R. Anthoney, Neuroanatomy and the Neurologic Exam, 2017
Fourthly, one finds inconsistency in usage. For example, Gilman and Newman (1987) define the limbic system as “a collection of interconnected but not contiguous structures in the telencephalon,” which they proceed to list; no structures belonging to the hypothalamus or brain stem are included (p. 193). Elsewhere, however, they state that “The orbital area is widely connected to structures of the limbic system, including … hypothalamus, and midbrain” (p. 209), and describe “The mammillary peduncle”, a pathway carrying fibers from the brain stem: (p. 1941 as one of the “Pathways carrying inputs from limbic system structures” (p. 193). As another example, Fig. 16–1 in Snell (1980), “showing structures that form the limbic system” (p. 276), shows the “habenular nuclei,” the “Stria medullaris thalami,” the “Olfactory' bulb,” the “Olfactory tract,” and the “Anterior commissure,” none of which is included in the listing of limbic-system structures on p. 275.
Developing the theory of the extended amygdala with the use of the cupric-silver technique
Published in Journal of the History of the Neurosciences, 2023
Soledad de Olmos, Alfredo Lorenzo
Using the Cu-Ag technique’s properties to reveal degeneration, de Olmos initiated a series of experiments to study the projection field of the bed nucleus of the stria terminalis and amygdala. Based on the results obtained, he considered that the stria terminalis could be formed by 3 components: dorsal, ventral and commissural (de Olmos 1971, 1972; de Olmos and Ingram 1972; see Figure 3). These studies demonstrated that fibers are arranged in such a way that the longer axons occupy a more medial position than the shorter ones (Figure 3a–b). A dorsoventral arrangement was apparent, especially with regard to the medial long-projecting fibers. This supported the division of the stria terminalis into dorsal and ventral components, with the “commissural” component lying between the medial and lateral portions (Figure 3a–c). This concept was also supported by the fact that fibers of the dorsal component reached the basal telencephalic centers and the medial hypothalamus, while those of the medial portion of the ventral component reached the central core of the ventromedial hypothalamic nucleus (Figure 3c; see de Olmos 1971, 1972; de Olmos and Ingram 1972).
Co-treatment of AMPA endocytosis inhibitor and GluN2B antagonist facilitate consolidation and retrieval of memory impaired by β amyloid peptide
Published in International Journal of Neuroscience, 2022
Fatemeh Ashourpour, Adele Jafari, Parvin Babaei
It should be noticed that NMDARs are heterotetrameric complexes composed of different subunits: Glutamate [NMDA] receptor subunit zeta-1 (GluN1), GluN2 Glutamate [NMDA] receptor subunit epsilon-2 (GluN2A-D), Glutamate [NMDA] receptor subunit 3A(GluN3A) and Glutamate [NMDA] receptor subunit 3 (GluN3). They form functional channels with different physiological and pharmacological properties in terms of voltage-dependency and agonist affinity [20]. GluN2A and GluN2B subunits are the predominant GluN2 subunits in the forebrain. In the telencephalon GluN2A subunit, seems to be located mainly at the synaptic sites and implicate in the protective pathways of learning and memory, whereas GluN2B is located mainly at the extrasynaptic sites and increase neuronal vulnerability [21]. GluN2C is expressed in glial cells and can modulate the excitability of NMDARs and also is involved in the consolidation of learned fear responses in the amygdala [22]. Finally, GluN2D is mostly located in the interneurons and mediates excitatory synapses of the CA1 pyramidal cells during the developmental stage [23].
Hypertension linked to allostatic load: from psychosocial stress to inflammation and mitochondrial dysfunction
Published in Stress, 2019
Feres José Mocayar Marón, León Ferder, Fernando Daniel Saraví, Walter Manucha
Of central interest for the present review, the brain is critical as a modulator and stress adapter organ (Karatsoreos & McEwen, 2011) and becomes essential for predictive regulation of the internal milieu (Sterling, 2014). Functions such as emotional processing, memory, cognition and, therefore, recognition and reaction to stress, are executed by the limbic system. The relevant circuit is composed of the telencephalon, the medial prefrontal cortex (mPFC), the amygdala and the hippocampus. The mPFC, amygdala, and hippocampus project their fibers and form an interconnected network of emotional and cognitive regulation (Herman et al., 2003). Output of these nuclei also converges on subcortical sites, primarily within anteroventral and posteroventral subregions of the bed nucleus of the stria terminalis (BST), distinct regions of the hypothalamus (e.g. lateral hypothalamic area, medial preoptic area, and posterior hypothalamus), and the brainstem (e.g. ventrolateral medulla, raphe nuclei, subfornical organ, locus coeruleus, and nucleus of the solitary tract -NTS-) (Ulrich-Lai & Herman, 2009). The hierarchical disposition allows the transduction of emotional stimuli in physiological reactions through synapses with sympathetic and parasympathetic preganglionic neurons (Myers, 2017). The prefrontal cortex integrates several inputs arriving from neocortical and limbic structures – and feeds back to both (Sterling, 2012).